Answer:
Step-by-step explanation:
[tex]100 (0.96)^{25} =[/tex] around 36.04
In a recent​ year, the total scores for a certain standardized test were normally​ distributed, with a mean of 500 and a standard deviation of 10.4. A) Find the probability that a randomly selected medical student who took the test had a total score that was less than 484. The probability that a randomly selected medical student who took the test had a total score that was less than 484 is:_______.B) Find the probability that a randomly selected study participant's response was between 4 and 6 The probability that a randomly selected study participant's response was between 4 and 6 is:_______.C) Find the probability that a randomly selected study participant's response was more than 8. The probability that a randomly selected study participant's response was more than 8 is:________.
Answer:
A) The probability that a randomly selected medical student who took the test had a total score that was less than 484 = 0.06178
B) The probability that a randomly selected study participant's response was between 504 and 516 = 0.29019
C) The probability that a randomly selected study participant's response was more than 528 = 0.00357
D) Option D is correct.
Only the event in (c) is unusual as its probability is less than 0.05.
Step-by-step explanation:
The b and c parts of the question are not complete.
B) Find the probability that a randomly selected study participant's response was between 504 and 516
C) Find the probability that a randomly selected study participant's response was more than 528.
D) Identify any unusual event amongst the three events in A, B and C. Explain the reasoning.
a) None.
b) Events A and B.
C) Event A
D) Event C
Solution
This is a normal distribution problem with
Mean = μ = 500
Standard deviation = σ = 10.4
A) Probability that a randomly selected medical student who took the test had a total score that was less than 484 = P(x < 484)
We first normalize or standardize 484
The standardized score for any value is the value minus the mean then divided by the standard deviation.
z = (x - μ)/σ = (484 - 500)/10.4 = - 1.54
To determine the required probability
P(x < 484) = P(z < -1.54)
We'll use data from the normal distribution table for these probabilities
P(x < 484) = P(z < -1.54) = 0.06178
B) Probability that a randomly selected study participant's response was between 504 and 516 = P(504 ≤ x ≤ 516)
We normalize or standardize 504 and 516
For 504
z = (x - μ)/σ = (504 - 500)/10.4 = 0.38
For 516
z = (x - μ)/σ = (516 - 500)/10.4 = 1.54
To determine the required probability
P(504 ≤ x ≤ 516) = P(0.38 ≤ z ≤ 1.54)
We'll use data from the normal distribution table for these probabilities
P(504 ≤ x ≤ 516) = P(0.38 ≤ z ≤ 1.54)
= P(z ≤ 1.54) - P(z ≤ 0.38)
= 0.93822 - 0.64803
= 0.29019
C) Probability that a randomly selected study participant's response was more than 528 = P(x > 528)
We first normalize or standardize 528
z = (x - μ)/σ = (528 - 500)/10.4 = 2.69
To determine the required probability
P(x > 528) = P(z > 2.69)
We'll use data from the normal distribution table for these probabilities
PP(x > 528) = P(z > 2.69) = 1 - P(z ≤ 2.69)
= 1 - 0.99643
= 0.00357
D) Only the event in (c) is unusual as its probability is less than 0.05.
Hope this Helps!!!
HELPPPPPPWhich is the simplified form of -7 +5-12?
1
12
S
O M - 512
12
S
o
1
12
S
Answer:
Step-by-step explanation:
[tex]r^{-7} +s^{-12} \\Use Negative Power Rule: x^{-a} =\frac{1}{x^{a} } \\r^{\frac{1}{7} } +s^{\frac{1}{12} } \\[/tex]
I hope i am correct
Los dueños de un restaurante cultivan sus propios
tomates, hierbas aromáticas, acelgas y otros vegetales
que utilizan en la preparación de sus comidas. Para el
riego de sus plantas, han construido un reservorio, cuya
capacidad es de 6,25 m3. Si al cabo de unos días han
utilizado los 2/3 de esta cantidad, ¿cuántos metros
cúbicos de agua todavía quedan en el reservorio y a
cuántos litros equivale?
(Considera 1 m3 = 1000 L).
Answer:
Quedan 2.083 m^3 de agua en el reservorio.
Equivalen a 2083 litros.
Step-by-step explanation:
Los dueños del restaurante tienen un reservorio de agua cuyo volumen es de 6.25 m^3.
Si han utilizado 2/3 del reservorio, esto implica que aún quedan en el reservorio una tercera parte del volumen original (1/3).
Entonces, la cantidad de metros cúbicos (m^3) de agua que quedan en el reservorio se puede calcular como:
[tex]V=(1/3)\cdot V_0=(1/3)\cdot6.25\,m^3=2.083\,m^3[/tex]
Este valor equivale a un volumen en litros de:
[tex]V=2.083\,m^3\cdot \dfrac{1,000\,l}{1m^3}=2,083\,l[/tex]
For an exam given to a class, the students' scores ranged from 34 to 99 , with a mean of 78 . Which of the following is the most realistic value for the standard deviation: -14,3,0,56,15?
Clearly explain what's unrealistic about each of the other values.
Answer:
The most realistic value for the standard deviation is 15.
Step-by-step explanation:
The standard deviation of a distribution is a measure of dispersion. It is a measure of the spread of the distribution from the mean of the distribution. It expresses how far most of the distribution is from the mean.
Mathematically, the standard deviation is given as the square root of variance. And variance is an average of the squared deviations from the mean.
Mathematically,
Standard deviation = σ = √[Σ(x - xbar)²/N]
x = each variable (ranges from 34 to 99)
xbar = mean = 78
N = number of variables
Now taking the given possible values of the standard deviation one at a time,
-14
The standard deviation cannot be negative as it is a square root of the average of the sum of square deviations from the mean. Since the square of a number cannot be negative, it directly translates that the standard deviation cannot be negative.
3
A small standard deviation like 3 indicates that the distribution mostly centres about the mean, with very little variation. And the distribution given has a mean (78) that is very far away from at least one of the variables in the distribution. Hence, 3 is too low to pass ad the standard deviation of this distribution described.
0
A standard deviation of 0 indicates that all the variables in the distribution have the same value as the mean. That is, the distribution only contains 1 number, probably multiple times. So, this cannot be the standard deviation for the distribution described.
56
This value represents a value that is too high to express the spread of the distribution described. The mean (78) is very close to the maximum value of the distribution, and far away from the lower value(s), indicating that most of the distribution is in and around the upper values with a few variables closer to the lower limit. A standard deviation as high as 56 for a mean of 78 translates to a distribution with most of variables far from the mean, which isn't the case here.
Moreso, a simple add of the standard deviation to the mean or subtracting the standard deviation from the mean should give at least one of the results with values within the distribution.
(Mean) + (Standard deviation) = 78 + 56 = 134 >> 99 (outside distribution)
(Mean) + (Standard deviation) = 78 - 56 = 22 << 34 (also outside the distribution)
15
This is the most realistic value for the standard deviation as it represents what the distribution described above is.
The mean (78) being close to the maximum value of the distribution, and far away from the lower value(s) indicates that most of the distribution is in and around the upper values with a few variables closer to the lower limit.
So, 15 indicates a perfect blend of small deviations due to the high values close to the mean and the very high deviation from the evidently few lower values.
(Mean) + (Standard deviation) = 78 + 15 = 93 < 99 (within distribution)
(Mean) + (Standard deviation) = 78 - 15 = 63 > 34 (also within the distribution)
Hope this Helps!!!
When The most realistic value for the standard deviation is 15.
Step-by-step explanation:
Standard deviation The standard deviation of a distribution is a measure of dispersion. also, It is a measure of the spread of the distribution from the mean of the distribution. when It expresses how far most of the distribution is from the mean. Then according to Mathematically, the standard deviation is given as the square root of variance. And also variance is an average of the squared deviations from the mean.mathematically,When Standard deviation is = σ = √[Σ(x - xbar)²/N]After that x = each variable (ranges from 34 to 99)then xbar is = mean = 78Now N is = number of variablesThen we take the given possible values of the standard deviation one at a time, -14 after that The standard deviation cannot be negative as it is a square root of the average of the sum of square deviations from the mean. Since the square of a number cannot be negative, also it directly translates that the standard deviation cannot be negative. After that 3 no when A small standard deviation like 3 indicates that the distribution mostly centers about the mean, with very little variation. And also the distribution given has a mean (78) that is very far away from at least one of the variables in the distribution. Hence proof that is, 3 is too low to pass ad the standard deviation of this distribution described. Then 0 when A standard deviation of 0 indicates that all the variables in the distribution have the same value as the mean. That means is, the distribution only contains 1 number, probably multiple times. So that, this can't be the standard deviation for the distribution described. Now 56 This value represents a value that is too high to express the spread of the distribution described. when The mean (78) is very close to the maximum value of the distribution, and also far away from the lower value(s), indicating that most of the distribution is in and also around the upper values with a few variables closer to the lower limit. when A standard deviation as high as 56 for a mean of 78 translates to a distribution with most of the variables far from the mean, which isn't the case here. More so, when a simple addition of the standard deviation to the mean or subtracting the standard deviation from the mean should have given at least one of the results with values within the distribution.After that (Mean) + (Standard deviation) = 78 + 56 = 134 >> 99 (outside distribution)Then (Mean) + (Standard deviation) = 78 - 56 = 22 << 34 (also outside the distribution) Now last digit 15 This is the most realistic and also a value for the standard deviation as it represents what the distribution described above is.When The mean (78) is close to the maximum value of the distribution, and also far away from the lower value(s) indicates that most of the distribution is in and also that around the upper values with a few variables closer to the lower limit.So that, 15 indicates a perfect blend of small deviations due to the high values close to the mean and also the very high deviation from the evidently few lower values.Then (Mean) + (Standard deviation) = 78 + 15 = 93 < 99 (within distribution) After that (Mean) + (Standard deviation) =Thus, 78 - 15 = 63 > 34 (also within the distribution)
Find out more information about standard deviation here:
https://brainly.com/question/25309029
Plz help! U will get full points!
Answer:
2 wild cards
Step-by-step explanation:
Typical would mean most often
2 wild cards shows up 6 times which is most often
What’s the correct answer for this question?
Answer:
The last option is the correct choice 33.5
Step-by-step explanation:
[tex]V=\pi r^2\frac{h}{3} \\=\pi 2^2\frac{8}{3} \\=33.51\\=33.5[/tex]
Answer:
D
Step-by-step explanation:
In the attached file
Angle θ is in standard position. If (8, -15) is on the terminal ray of angle θ, find the values of the trigonometric functions.
sin(θ) =
cos(θ) =
tan(θ) =
csc(θ) =
sec(θ) =
✔ 17/8
cot(θ) =
✔ -8/15
i have only gotten the last two right and i need help with the others.
Answer:
cos =1/ sec
=8/17
tan =1/cot
= -15/8
sin = 15/17 or -15/17
cosec = 1/ sin
= 17/15 or -17/15
Answer:
Did the same assignment. lol can see how that went but here's the answers. hope it helps.
If 4000 hours= 240,000 minutes and you make a 10 minute video, how many people will need to view the video to get 4000 hours of view time?
Answer:
24000
Step-by-step explanation:
because 24000 * 10 =240000
Please answer this correctly as soon as possible.I have to finish this today. A triangular prism is 19 yards long and has a triangular face with a base of 12 yards and a height of 8 yards. The other two sides of the triangle are each 10 yards. What is the surface area of the triangular prism?
total SA = 764 yd²
A triangular prism is 13 yards long and has a triangular face with a base of 12 yards and a height of 8 yards. The other two sides of the triangle are each 10 yards. What is the surface area of the triangular prism?
See attachment.
if length = 13 yards then total SA = 512 yd²
if length = 19 yards then total SA = 764 yd²
ASAPPPP
I HAVE AND IMAGE BELOW
Answer:
#1
Step-by-step explanation:
The associative property of addition states that we can "flip" two expressions that are being added. Therefore, our answer is the first one because it can be rewritten as 3x + (-7y) which then is equivalent to -7y + 3x.
help asap giving branlist!!!
Answer:
option 2
Step-by-step explanation:
Because (0, 900) is a point on the line it means that it costs $900 to make the commercial. A slope of 110 means that they pay $110 every time it's aired so the answer is Option 2.
A girl threw a marble 15 m vertically up in the air which later fell and settled at the bottom of a lake 7 m deep. Find the total distance travelled by the marble while falling down?
Answer:
22 m
Step-by-step explanation:
Total distance travelled by marble while falling down = height above surface of lake + depth of lake = 15 + 7 = 22 m
The distance between (2,0) and (5, -1) is
Answer:
(3, -1)
Step-by-step explanation:
5-2=3
0-1=-1 (keep 0, change - to a +, flip 1 to a -1)
Use the equation and type the ordered-pairs. y = log 2 x {(1/2, a0), (1, a1), (2, a2), (4, a3), (8, a4), (16, a5)}
Answer:
the answer is 1/2,a0
Step-by-step explanation:
helpppppppppppppppppppppppppppppppppp
Answer:
answer is 2/3
Step-by-step explanation:
probability it is an eclair is 1/15=3/(3+2x+6+x)= 1/(x+3)
so x+3=15 and then x = 12
so the probability it is a humbug is (2*12+6)/(3*12+9) = 30/45 = 2/3
A researcher has developed a new drug designed to reduce blood pressure. In an experiment, 21 subjects were assigned randomly to the treatment group and received the new experimental drug. Based on these data, the computed two-sample t statistic is:
Answer:
I think the complete question should be:
A researcher has developed a new drug designed to reduce blood pressure. In an experiment, 21 subjects were assigned randomly to the treatment group and received the new experimental drug. The other 23 subjects were assigned to the control group and received a standard well known treatment. After a suitable period of time, the reduction in blood pressure for each subject was recorded.
Treatment group n = 21, x1 mean = 23.48, sd = 8.01
Control group n = 23, x2 = 18.52, sd = 7.15
Based on these data, the computed two-sample t statistic is:
Step-by-step explanation:
Since the variances to be calculated from the sd are unequal we use this formula:
t statistics = (x1 - x2) / [(sd1²/n1) + (sd2²/n2) where n1 = 21, x1 mean = 23.48, sd1 = 8.01, n2 = 23, x2 = 18.52, sd2 = 7.15
Thus, we have
test statistic= (23.48-18.52) / [(8.01²/21) + (7.15²/23)]
Test statistics = 4.96 / (324.36/21)+(51.12/23)]
Test statistics = 4.96/ (15.45+2.43)
t statistic = 4.96 / 17.88
t statistics = 0.2774
I hope that helps, you can use this to solve for tours if the values are not the same
Captain Jessica has a ship, the H.M.S. Khan. The ship is two furlongs from the dread pirate Michael and his merciless band of thieves.
The Captain has probability \dfrac{1}{2}
2
1
start fraction, 1, divided by, 2, end fraction of hitting the pirate ship. The pirate only has one good eye, so he hits the Captain's ship with probability \dfrac{1}{6}
6
1
start fraction, 1, divided by, 6, end fraction.
If both fire their cannons at the same time, what is the probability that both the pirate and the Captain hit each other's ships?
Answer:
[tex]\dfrac{1}{12}[/tex]
Step-by-step explanation:
Probability of the captain hitting the pirate ship [tex]=\dfrac{1}{2}[/tex]
Probability of the pirate hitting the captain's ship [tex]=\dfrac{1}{6}[/tex]
If both fire cannons at the same time, the probability that both the pirate and the captain hit each other's ship
=P(Captain Hits AND Pirate Hits)
=P(Captain Hits) X P(Pirate Hits)
[tex]=\dfrac{1}{2} X \dfrac{1}{6}\\\\=\dfrac{1}{12}[/tex]
Find the slope and y-intercept of this linear function:
2x + x = 4(y - 1)
Answer:
slope: 3/4y-intercept: 1Step-by-step explanation:
Solve for y to put the equation in slope-intercept form.
3x = 4y -4 . . . . . eliminate parentheses, collect terms
3x +4 = 4y . . . . . add 4
y = 3/4x +1 . . . . . divide by 4
The slope is the x-coefficient: 3/4.
The y-intercept is the constant: 1.
Construct the indicated confidence interval for the difference between the two population means. Assume that the two samples are independent simple random samples selected from normally distributed populations. Do not assume that the population standard deviations are equal.
A paint manufacturer wished to compare the drying times of two different types of paint. Independent simple random samples of 11 cans of type A and 9 cans of type B were selected and applied to similar surfaces. The drying times, in hours, were recorded. The summary statistics are as follows.
Type A
x-bar1 = 75.7 hrs.
s1 = 4.5 hrs.
n1 = 11
Type B
x-bar2 = 64.3 hrs.
s2 = 5.1 hrs.
n2 = 9
Construct a 98% confidence interval for the difference for the mean drying time between paint A and paint B.
A. 6.08 hrs < μ1 - μ2 < 16.72 hrs
B. 5.85 hrs < μ1 - μ2 < 16.95 hrs
C. 5.78 hrs < μ1 - μ2 < 17.02 hrs
D. 5.92 hrs < μ1 - μ2 < 16.88 hrs
Answer:
Step-by-step explanation:
The formula for determining the confidence interval for the difference of two population means is expressed as
Confidence interval = (x1 - x2) ± z√(s²/n1 + s2²/n2)
Where
x1 = sample mean of type A paint
x2 = sample mean of type B paint
s1 = sample standard deviation type A paint
s2 = sample standard for type B paint
n1 = number of samples of type A paint
n2 = number of samples of type B paint
From the information given,
x1 = 75.7
s1 = 4.5
n1 = 11
x2 = 64.3
s2 = 5.1
n2 = 9
x1 - x2 = 75.7 - 64.3 = 11.4
√(s1²/n1 + s2²/n2) = √(4.5²/11 + 5.1²/9) = √4.709
Degree of freedom = (n1 - 1) + (n2 - 1)
df = (11 - 1) + (9 - 1) = 18
For the 98% confidence interval, the z score from the t distribution table is 2.552
Margin of error = 2.552√4.709 = 5.55
The upper boundary for the confidence interval is
11.4 + 5.55 = 16.95 hours
The lower boundary for the confidence interval is
11.4 - 5.55 = 5.85 hours
The correct option is
B. 5.85 hrs < μ1 - μ2 < 16.95 hrs
Meru Peak is 765 m higher than Mt. Kilimanjaro. If the sum of their heights is 12,555 m, find the height of Mt. Kilimanjaro.
Answer:
Step-by-step explanation:
Let P=Mount Peak
Let K=Mount Killimanjaro
The equation should then be
12555=P+K ...1
P=K+765 ... 2
sub equation 2 into 1
12555=P+P+765
12555=2P+765
12555-765=2P+765-765 (subtracting 765 from both sides)
11790=2P
P=5895, now that we know P
we just make a new equation that was similiar to 1
12555=5895+K
K=6660
the height of Mount K is 6660 Metres
In the circle below, CD is a diameter. If AE=10, CE=4, and AB=16, what is
the length of the radius of the circle?
Please Help ASAP
Answer:
(D)9.5 Units
Step-by-step explanation:
We have two chords CD and AB intersecting at E.
Using the theorem of intersecting chords
AE X EB =CE X ED
AE=10CE=4AB=16AB=AE+EB
16=10+EB
EB=16-10=6
Therefore:
AE X EB =CE X ED
10 X 6 = 4 X ED
ED =60/4 =15
Therefore:
CD=CE+ED
=4+15
CD=19
Recall that CD is a diameter of the circle and;
Radius =Diameter/2
Therefore, radius of the circle =19/2 =9.5 Units
Problem 3.3.9 • (a) Starting on day 1, you buy one lottery ticket each day. Each ticket is a winner with probability 0.1. Find the PMF of K, the number of tickets you buy up to and including your fifth winning ticket. (b) L is the number of flips of a fair coin up to and including the 33rd occurrence of tails. What is the PMF of L? (c) Starting on day 1, you buy one lottery ticket each day. Each ticket is a winner with probability 0.01. Let M equal the number of tickets you buy up to and including your first winning ticket. What is the PMF of M?
Answer:
a) The probability mass function of K = [tex]P(K=k) = \binom{k-1}{4}0.1^{4}*0.9^{k-5} ; k =5,6,...[/tex]
b)
c)
Step-by-step explanation:
a) Let p be the probability of winning each ticket be = 0.1
Then q which is the probability of failing each ticket = 1 - p = 1 - 0.1 = 0.9
Assume X represents the number of failure preceding the 5th success in x + 5 trials.
The last trial must be success whose probability is p = 0.1 and in the remaining (x + r- 1) ( x+ 4 ) trials we must have have (4) successes whose probability is given by:
[tex]\binom{x+r-1}{r-1}*p^{r-1}*q^{x} = \binom{x+4}{4}0.1^{4}*0.9^{x} ; x =0, 1, .........[/tex]
Then, the probability distribution of random variable X is
[tex]P(X=x) = \binom{x+4}{4}0.1^{4}*0.9^{x} ; x =0, 1, .........[/tex]
where;
X represents the negative binomial random variable.
K= X + 5 = number of ticket buy up to and including fifth winning ticket.
Since K =X+5 this signifies that X = K-5
as X takes value 0, 1 ,2,...
K takes value 5, 6 ,...
Therefore:
The probability mass function of K = [tex]P(K=k) = \binom{k-1}{4}0.1^{4}*0.9^{k-5} ; k =5,6,...[/tex]
b)
Let p represent the probability of getting a tail on a flip of the coin
Thus p = 0.5 since it is a fair coin
where L = number of flips of the coin including 33rd occurrence of tails
Thus; the negative binomial distribution of L can be illustrated as:
[tex]P(X=x) = \binom{x-1}{r-1}(1-p)^{x-r}p^r[/tex]
where
X= L
r = 33 &
p = 0.5
Since we are looking at the 33rd success; L is likely to be : L = 33,34,35...
Thus; the PMF of L = [tex]P(L=l) = \binom{l-1}{33-1}(1-0.5)^{l}(0.5)^{33} \\ \\ \\ \mathbf{P(L=l) = \binom{l-1}{33-1}(0.5)^{l} }[/tex]
c)
Given that:
Let M be the random variable which represents the number of tickets need to be bought to get the first success,
also success probability is 0.01.
Therefore, M ~ Geo(0.01).
Thus, the PMF of M is given by:
[tex]P(M = m) = (1-0.01)^{m-1} * 0.01 , \ \ \ since \ \ \ (m = 1,2,3,4,....)[/tex]
[tex]P(M=m) = (0.99)^{m-1} * 0.01 , m = 1,2,3,4,....[/tex]
What is the range of the function y = -x ^2 + 1?
A. y ≤ -1
B. y ≥ -1
C. y ≤ 1
D. y ≥ 1
Answer:
C. y ≤ 1
Step-by-step explanation:
The maximum value of the function is 1. So, the range is all values of y less than or equal to that.
y ≤ 1
3. Find the mean and range of the following data.
14, 14, 15, 15, 16, 15, 15, 16
A 15; 15
B 12; 15
C 12; 2
D 15; 2
Answer:
D: 15 and 2
Step-by-step explanation:
Mean
To find the mean, or average, add up all the values in the data set,then divide by the number of values in the data set.
1. Add up all the values
Values: 14, 14, 15, 15, 16, 15, 15, 16
Add them :14+14+15+ 15+16+15+15+16=120
120
2. Divide by the number of values
Count how many numbers are in the data set. In this case there are 8. Divide 120 by 8.
120/8=15
The mean is 15
Range
To find the range, subtract the smallest number in the set from the biggest number in the set.
14, 14, 15, 15, 16, 15, 15, 16
Biggest number: 16
Smallest number: 14
biggest-smallest
16-14=2
The range is 2
Therefore, the answer is D: 15 and 2
observation means number.
mean= sum of all observation ÷ number of observation
= 14+ 14+ 15+ 15+ 16+ 15+ 16
7
= 105
7
= 15
range= the highest observation - lowest observation
= highest number- 16
lowest number- 14
= 16-14
= 2
therefore the answer is
OPTION- D 15;2
Please answer this correctly
Answer:
28 and 7
35
Step-by-step explanation:
The area of a triangle is base*height/2, no matter the shape.
So the big one is 8*7/2 = 28 in²
And the little one is 2*7/2 = 7 in²
The total trapezoid therefore has an area of 28+7=35 in²
Please help!!! Which of the following is equal to the rational expression when x ≠ -2 or 3? x^2+5x+6/x^2-x-6
Answer:
see below
Step-by-step explanation:
These are always simplified by cancelling common factors from numerator and denominator. In order to do that, you have to factor the expressions. The restrictions on x give a clue as to the factors of the denominator.
[tex]\dfrac{x^2+5x+6}{x^2-x-6}=\dfrac{(x+3)(x+2)}{(x-3)(x+2)}=\boxed{\dfrac{x+3}{x-3}}[/tex]
The best possible statement to your question is x+3 / x-3
The amount of pollutants that are found in waterways near large cities is normally distributed with mean 9 ppm and standard deviation 1.5 ppm. 38 randomly selected large cities are studied. Round all answers to 4 decimal places where possible.
1. What is the distribution of XX? XX ~ N(,)
2. What is the distribution of ¯xx¯? ¯xx¯ ~ N(,)
3. What is the probability that one randomly selected city's waterway will have more than 9.6 ppm pollutants?
4. For the 37 cities, find the probability that the average amount of pollutants is more than 9.6 ppm.
5. For part d), is the assumption that the distribution is normal necessary? YesNo
6. Find the IQR for the average of 37 cities.
Q1 = ppm
Q3 = ppm
IQR: ppm
Answer:
Step-by-step explanation:
Hello!
There are two values of n in the text, I'll use the one that appears in all the questions.
The variable of interest is
X: pollutants found in waterways near large cities. (ppm)
This variable has a normal distribution with parameters μ= 9ppm and σ= 1.5ppm
1) X~N(μ;σ²)
X~N(9;2.25)
2) The distribution of the sample mean is X~N(μ;σ²/n)
σ²/n= 2.25/37= 0.06
X~N(9;0.06)
3) P(X>9.6)
To calculate this probability you have to use the standard normal distribution. Using the population parameters, you can calculate the corresponding Z value:
Z= (X-μ)/σ= (9.6-9)/1.5= 0.4
P(Z>0.4)= 1-P(Z≤0.4)= 1 - 0.65542= 0.34458
The probability of selecting a city at random and finding 9.6ppm pollutants.
4) In this item, instead of calculating the probability of one value of the variable you have to calculate the probability of the sample average taking a determined value. Because of this, you have to work using the distribution of the sample mean, instead of the distribution of the variable.
P(X[bar]>9.6)
Z= (X[bar]-μ)/(σ/√n)= (9.6-9)/√0.06= 2.45
P(Z>2.45)= 1 - P(Z≤2.45)= 1 - 0.99286= 0.00714
5) The assumption of a normal distribution is not necessary for item 4. Since the sample size is large enough (greater than 30) you can apply the central limit theorem and approximate the distribution of the sample mean to normal, regarding the distribution of the original variable.
6)
In this case, you have to work starting with the standard normal distribution and then "translate" the Z values into values of the average amount of pollutants.
The first quartile divides the bottom 25% of the distribution from the top 75%, symbolically:
P(Z≤z₁)= 0.25
z₁= -0.674
z₁= (X[bar]-μ)/(σ/√n)
z₁*(√n/σ)=X[bar]-μ
X[bar]=z₁*(√n/σ)+μ
X[bar]=(-0.674)*(√37/1.5)+9= 6.27ppm
The third quartile divides the bottom 75% of the distribution from the top 25%, symbolically:
P(Z≤z₂)= 0.75
z₂= 0.674
z₂= (X[bar]-μ)/(σ/√n)
z₂*(√n/σ)=X[bar]-μ
X[bar]=z₂*(√n/σ)+μ
X[bar]=(0.674)*(√37/1.5)+9= 11.7.3ppm
IQR= Q₃-Q₁= 11.73-6.27= 5.46ppm
I hope this helps!
at the last minute deal Don and Mary booked a 7 day cruise for a total of $670. If the normal price for a couple is $1340, what discount percent did Don ans Mary recieve?
Answer:50%
Step-by-step explanation:670/1340 = 1/2 = 50%
Write the point slope form of an equation of the line through the points (-2,6) and (3,-3)
Answer:
A.
Step-by-step explanation:
So first you need to find the slope:
[tex]\frac{-2-6}{3+2} =-\frac{8}{5}[/tex]
Since it's point slope, you have to use a point:
It's either:
[tex](y - 6)=-\frac{8}{5}(x+2)[/tex]
or
[tex](y+2)=-\frac{8}{5}(x-3)[/tex]
Check which answer has those:
A.
The solution is Option A.
The equation of line is y - 6 = ( -8/5 ) ( x + 2 ) where the slope is -8/5
What is an Equation of a line?The equation of a line is expressed as y = mx + b where m is the slope and b is the y-intercept
And y - y₁ = m ( x - x₁ )
y = y-coordinate of second point
y₁ = y-coordinate of point one
m = slope
x = x-coordinate of second point
x₁ = x-coordinate of point one
The slope m = ( y₂ - y₁ ) / ( x₂ - x₁ )
Given data ,
Let the equation of line be represented as A
Now , the value of A is
Let the first point be P ( -2 , 6 )
Let the second point be Q ( 3 , -2 )
The slope of the line between the point is given by m = ( y₂ - y₁ ) / ( x₂ - x₁ )
Substituting the values in the equation , we get
Slope m = ( 6 - ( - 2 ) ) / ( -2 - 3 )
On simplifying the equation , we get
Slope m = ( 8 / -5 ) = -8/5
Now , the equation of line is y - y₁ = m ( x - x₁ )
Substituting the values in the equation , we get
y - 6 = ( -8/5 ) ( x - ( -2 ) )
On simplifying the equation , we get
y - 6 = ( -8/5 ) ( x + 2 )
Hence , the equation of line is y - 6 = ( -8/5 ) ( x + 2 )
To learn more about equation of line click :
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Thirty percent of all telephones of a certain type are submitted for service while under warranty. Of these, 70% can be repaired, whereas the other 30% must be replaced with new units. If a company purchases ten of these telephones, what is the probability that exactly three will end up being replaced under warranty
Answer:
26.68% probability that exactly three will end up being replaced under warranty
Step-by-step explanation:
For each telephone under warranty, there are only two possible outcomes. Either they need to be replaced, or they do not need to be replaced. Each telephone is independent of other telephones. So we use the binomial probability distribution to solve this question.
Binomial probability distribution
The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.
[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]
In which [tex]C_{n,x}[/tex] is the number of different combinations of x objects from a set of n elements, given by the following formula.
[tex]C_{n,x} = \frac{n!}{x!(n-x)!}[/tex]
And p is the probability of X happening.
30% must be replaced with new units
This means that [tex]p = 0.3[/tex]
If a company purchases ten of these telephones, what is the probability that exactly three will end up being replaced under warranty
This is [tex]P(X = 3)[/tex] when [tex]n = 10[/tex]. So
[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]
[tex]P(X = 3) = C_{10,3}.(0.3)^{3}.(0.7)^{7} = 0.2668[/tex]
26.68% probability that exactly three will end up being replaced under warranty
