Answer:
Step 1: The estimate the proportion of tenth graders reading at or below the eighth grade level is 0.2.
Step 2: The 99% confidence interval for the population proportion of tenth graders reading at or below the eighth grade level is (0.181, 0.219).
Step-by-step explanation:
In a sample with a number n of people surveyed with a probability of a success of [tex]\pi[/tex], and a confidence level of [tex]1-\alpha[/tex], we have the following confidence interval of proportions.
[tex]\pi \pm z\sqrt{\frac{\pi(1-\pi)}{n}}[/tex]
In which
z is the z-score that has a p-value of [tex]1 - \frac{\alpha}{2}[/tex].
Suppose a sample of 2845 tenth graders is drawn. Of the students sampled, 2276 read above the eighth grade level.
So 2845 - 2276 = 569 read below, and the estimate of the proportion of tenth graders reading at or below the eighth grade level is:
[tex]\pi = \frac{569}{2845} = 0.2[/tex], and the answer to step 1 is 0.2.
The sample size is [tex]n = 2845[/tex]
99% confidence level
So [tex]\alpha = 0.01[/tex], z is the value of Z that has a p-value of [tex]1 - \frac{0.01}{2} = 0.995[/tex], so [tex]Z = 2.575[/tex].
The lower limit of this interval is:
[tex]\pi - z\sqrt{\frac{\pi(1-\pi)}{n}} = 0.2 - 2.575\sqrt{\frac{0.2*0.8}{2845}} = 0.181[/tex]
The upper limit of this interval is:
[tex]\pi + z\sqrt{\frac{\pi(1-\pi)}{n}} = 0.2 + 2.575\sqrt{\frac{0.2*0.8}{2845}} = 0.219[/tex]
The 99% confidence interval for the population proportion of tenth graders reading at or below the eighth grade level is (0.181, 0.219).
The height of a projectile fired upward is given by the formula
s = v0t − 16t2,
where s is the height in feet,
v0
is the initial velocity, and t is the time in seconds. Find the time for a projectile to reach a height of 96 ft if it has an initial velocity of 128 ft/s. Round to the nearest hundredth of a second.
Answer:
The projectile will reach a height of 96 feet after about 0.84 seconds as well as after about 7.16 seconds.
Step-by-step explanation:
The height of a projectile fired upward is given by the formula:
[tex]\displaystyle s = v_{0} t - 16t^2[/tex]
Where s is the height in feet, v₀ is the initial velocity, and t is the time in seconds.
Given a projectile with an initial velocity of 128 ft/s, we want to determine how long it will take the projectile to reach a height of 96 feet.
In other words, given that v₀ = 128, find t such that s = 96.
Substitute:
[tex](96) = (128)t-16t^2[/tex]
This is a quadratic. First, we can divide both sides by -16:
[tex]-6 = -8t+t^2[/tex]
Isolate the equation:
[tex]t^2 - 8t + 6 = 0[/tex]
The equation isn't factorable, so we can consider using the quadratic formula:
[tex]\displaystyle t = \frac{-b\pm\sqrt{b^2 - 4ac}}{2a}[/tex]
In this case, a = 1, b = -8, and c = 6. Substitute:
[tex]\displaystyle t = \frac{-(-8)\pm\sqrt{(-8)^2-4(1)(6)}}{2(1)}[/tex]
Simplify:
[tex]\displaystyle t = \frac{8\pm\sqrt{40}}{2} = \frac{8\pm 2\sqrt{10}}{2} = 4\pm \sqrt{10}[/tex]
Hence, our two solutions are:
[tex]\displaystyle t = 4+\sqrt{10} \approx 7.16\text{ or } t= 4-\sqrt{10} \approx 0.84[/tex]
So, the projectile will reach a height of 96 feet after about 0.84 seconds as well as after about 7.16 seconds.
Hi I need help how to solve this equation with explanation thank you
Answer:
A)x>-3
Step-by-step explanation:
as the circle is not coloured this means that -3 is not included so the ones that have
[tex] \geqslant \\ \leqslant [/tex]
are not answers and these means smaller or equal to/greater or equal to.
As the line is going to the right this means that x is greater than -3 so we use > for greater.
so in the end we get that the answer is x > -3
Consider the probability that greater than 26 out of 124 software users will call technical support. Assume the probability that a given software user will call technical support is 97%. Specify whether the normal curve can be used as an approximation to the binomial probability by verifying the necessary conditions.
Answer:
Since [tex]n(1-p) = 3.72 < 10[/tex], the normal curve cannot be used as an approximation to the binomial probability.
100% probability that greater than 26 out of 124 software users will call technical support.
Step-by-step explanation:
Test if the normal curve can be used as an approximation to the binomial probability by verifying the necessary conditions.
It is needed that:
[tex]np \geq 10[/tex] and [tex]n(1-p) \geq 10[/tex]
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.
Can be approximated to a normal distribution, using the expected value and the standard deviation.
The expected value of the binomial distribution is:
[tex]E(X) = np[/tex]
The standard deviation of the binomial distribution is:
[tex]\sqrt{V(X)} = \sqrt{np(1-p)}[/tex]
Normal probability distribution
Problems of normally distributed distributions can be solved using the z-score formula.
In a set with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the z-score of a measure X is given by:
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.
When we are approximating a binomial distribution to a normal one, we have that [tex]\mu = E(X)[/tex], [tex]\sigma = \sqrt{V(X)}[/tex].
Out of 124 software users
This means that [tex]n = 124[/tex]
Assume the probability that a given software user will call technical support is 97%.
This means that [tex]p = 0.97[/tex]
Conditions:
[tex]np = 124*0.97 = 120.28 \geq 10[/tex]
[tex]n(1-p) = 124*0.03 = 3.72 < 10[/tex]
Since [tex]n(1-p) = 3.72 < 10[/tex], the normal curve cannot be used as an approximation to the binomial probability.
Consider the probability that greater than 26 out of 124 software users will call technical support.
The lowest possible probability of those is 27, so, if it is 0, since it is considerably below the mean, 100% probability of being greater. We have that:
[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]
[tex]P(X = 27) = C_{124,27}.(0.97)^{27}.(0.03)^{97} = 0[/tex]
1 - 0 = 1
100% probability that greater than 26 out of 124 software users will call technical support.
what is the base? Look at picture.
Answer:
14
Step-by-step explanation:
The area of a parallelogram is
A = bh where b is the base and h is the height
140 = b*10
Divide each side by 10
140/10 = 10b/10
14 = b
HELPPPP PLZ
Witch statement is true about the value of |6|?
Answer:
The third choice is the correct one.
Step-by-step explanation:
The absolute value of six means that it's the distance from 0 to six, and that distance will be positive regardless of the number being negative or not.
Answer: The third answer is correct
Step-by-step explanation:
Since |6| is the absolute value of positive six, the value of an absolute value of any number is always positive.
A certain virus infects one in every 300 people. A test used to detect the virus in a person is positive 85% of the time if the person has the virus and 5% of the time if the person does not have the virus, (This 5% result is called a false positive.) Let A be the event "the person is Infected" and B be the event "the person tests positive", a) Find the probability that a person has the virus given that they have tested positive, l.e. find P(AB). Round your answer to the nearest tenth of a percent and do not include a percent sign. P(AIB)= % b) Find the probability that a person does not have the virus given that they test negative, I.e. find P(A'B'). Round your answer to the nearest tenth of a percent and do not include a percent sign. P(A'B') =
This question is solved using the conditional probability concept.
Using this concept, we find that:
a) P(AIB)= 5.3%b) P(A'|B') = 99.9%First, the concept is presented.
Conditional Probability
We use the conditional probability formula to solve this question. It is
[tex]P(A|B) = \frac{P(A \cap B)}{P(B)}[/tex]
In which
P(A|B) is the probability of event A happening, given that B happened.
[tex]P(A \cap B)[/tex] is the probability of both A and B happening.
P(B) is the probability of B happening.
----------------------------------------------------
Question a:
For relation with the formula presented above, I will change events A and B.
Event A: Person is infected.
Event B: Positive test.
Probability of a positive test:
85% = 0.85 out of 1/300 (person has the virus).5% = 0.05 out of 299/300(person does not have the virus)Thus:
[tex]P(B) = 0.85\frac{1}{300} + 0.05\frac{299}{300} = \frac{0.85\times1 + 0.05\times299}{300} = 0.0527[/tex]
Probability of a positive test and the person is infected.
85% = 0.85 out of 1/300. Thus:
[tex]P(A \cap B) = \frac{0.85}{300} = 0.0028[/tex]
Desired probability:
[tex]P(A|B) = \frac{P(A \cap B)}{P(B)} = \frac{0.0028}{0.0527} = 0.053[/tex]
0.053*100% = 5.3%, thus:
P(AIB)= 5.3%
---------------------
Question b:
Event A: Does not have the virus
Event B: Test negative.
Probability of a negative test:
100% - 85% = 15% = 0.15 out of 1/300 (person has the virus).100% - 5% = 95% = 0.95 out of 299/300(person does not have the virus)Thus:
[tex]P(B) = 0.15\frac{1}{300} + 0.95\frac{299}{300} = \frac{0.15\times1 + 0.95\times299}{300} = 0.9473[/tex]
Probability of a negative test and the person is not infected.
0.95 out of 299/300
Thus:
[tex]P(A \cap B) = \frac{0.95\times299}{300} = 0.9468[/tex]
Desired probability:
[tex]P(A|B) = \frac{P(A \cap B)}{P(B)} = \frac{0.9468}{0.9473} = 0.999[/tex]
0.999*100% = 99.9%, so:
P(A'|B') = 99.9%
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A bookkeeper needs to post the cost of the desk and the chair into his records. The cost of the desk is fives times the cost if the chair. The total cost of the desk and the chair is $720, what is the cost of the chair?
Answer:
120
Step-by-step explanation:
720÷6
why?
becoz 6= 1+5
1 is the cosy of the chair
5 is the cost of the desk
How does sample size affect determinations of statistical significance? The smaller the sample size, the more confident one can be in one's decision to reject or retain the null hypothesis. The smaller the sample size, the greater the probability that the variable has an effect. The larger the sample size, the more accurate the estimation of the true population value. The larger the sample size, the greater the probability that the variable has an effect.
Answer:
The larger the sample size, the more accurate the estimation of the true population value.
Step-by-step explanation:
As large will be the sample size more data will be shown and more are the c c changes of it being an estimate of a true population. The sample size can be determined on the basis of use of experience, target variance, confidence level, and target for power.Quadrilateral JKLM is rotated - 270° about the origin.
Draw the image of this rotation
Need a visual answer please! Thanks!
Answer:
Step-by-step explanation:
When the quadrilateral JKLM is rotated - 270° about the origin then the image of rotated quadrilateral is shown below.
What is rotation?"It is a transformation in which the object is rotated about a fixed point. "
For given question,
Quadrilateral JKLM is rotated - 270° about the origin.
This means, quadrilateral JKLM is rotated 270° clockwise about the origin.
We know, if point P(x, y) is rotated 270° clockwise or 90° anticlockwise then the coordinated of rotated point would be (-y, x).
From figure, the coordinates of the quadrilateral JKLM are:
J = (3, 3)
K = (5, -5)
L = (-3, -7)
M = (3, -3)
After rotating -270° about the origin the coordinates of the quadrilateral would be,
J' = (-3, 3)
K' = (5, 5)
L' = (7, -3)
M' = (3, 3)
And the image of the rotated quadrilateral J'K'L'M' is shown below.
Therefore, when the quadrilateral JKLM is rotated - 270° about the origin then the image of rotated quadrilateral is shown below.
Learn more about rotation here:
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Jill records the temperature outside every hour for 4 hours. She finds that the temperature dropped by the same amount each hour. After 4 hours, she finds that the temperature dropped a total of 20∘F. She writes this number sentence.
(−20)÷4=−5
What does the number sentence mean?
The total drop in temperature, −20∘F, divided by 4 hours equals −5∘F per hour. The temperature dropped 5∘F each hour.
The total number of drops, 20, divided by 4 hours equals 5 times per hour. The temperature dropped 5 times per hour.
The total number of hours, 20, divided by 4∘F equals 5 hours. The temperature dropped once every 5 hours.
The total drop in temperature, −20∘F, divided by 4∘F in the first hour, equals −5 drops. The temperature dropped 5 times.
Answer:
It is the first one, The total drop in temperature, −20∘F, divided by 4 hours equals −5∘F per hour. The temperature dropped 5∘F each hour.
Step-by-step explanation:
find the sum or difference of 4/5 - (-3 4/5)
Answer:
4 3/5
Step-by-step explanation:
4/5 - (-3 4/5)
Subtracting a negative is like adding
4/5 + 3 4/5
3 8/5
3 5/5 + 3/5
3+1+3/5
4 3/5
For a given function ƒ(x) = x2 – x + 1, the operation –ƒ(x) = –(x2 – x + 1) will result in a
A) reflection across the x-axis.
B) horizontal shrink.
C) reflection across the y-axis.
D) vertical shrink.
Given:
The function is:
[tex]f(x)=x^2-x+1[/tex]
To find:
The result of the operation [tex]-f(x)=-(x^2-x+1)[/tex].
Solution:
If [tex]g(x)=-f(x)[/tex], then the graph of f(x) is reflected across the x-axis to get the graph of g(x).
We have,
[tex]f(x)=x^2-x+1[/tex]
The given operation is:
[tex]-f(x)=-(x^2-x+1)[/tex]
So, it will result in a reflection across the x-axis.
Therefore, the correct option is A.
Answer:
A) reflection across the x-axis.
Step-by-step explanation: I took the test
Given f (x) = 4x - 3,g(2) = x3 + 2x
Find (f - g) (4)
Which facts are true for the graph of the function below? Check all that apply.
F(x)-(3/7)^x
Answer:
Step-by-step explanation:
A trolley travels in one direction at an average of 20 miles per hour, then turns around and travels on the same track in the opposite direction at 20 miles per hour of the total time waveling on the trolleys 3.5 hours, how far did the trolley travel in one direction?
mi
Enter your answer in the answer box and then click Check Answer
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9514 1404 393
Answer:
35 miles
Step-by-step explanation:
The relevant relation is ...
distance = speed × time
The total distance the trolley traveled is ...
d = (20 mi/h) × (3.5 h) = 70 mi
The distance is the same in both directions, so the trolley traveled half this distance in one direction.
The trolley traveled 35 miles in one direction.
Cho biết tỉ lệ máy tính bảng sử dụng hệ điều hành A là 70%, tỉ lệ máy tính bảng sử
dụng hệ điều hành W là 30%. Xác suất để một máy tính bảng có hệ điều hành sử dụng ổn định
(không phải cài đặt lại) trong 2 năm đầu tiên là 0, 75. Tỉ lệ sử dụng ổn định của các máy tính
bảng có hệ điều hành A cao hơn tỉ lệ sử dụng ổn định của các máy tính bảng có hệ điều hành
W là 20%. Hãy tính xác suất để một máy tính bảng có hệ điều hành W sử dụng ổn định trong
2 năm đầu tiên.
Answer:
máy ...
xác suất để một máy tính bảng có hệ điều hành B sử dụng ổn định trong 2 năm đầu tiên. Add answer
Which statement is true about a line plot? A. A line plot shows the frequency of an interval of values of any given data set. B. A line plot shows the first quartile, but not the second quartile of any given data set. C. A line plot shows the frequency of the individual values of any given data set. D. A line plot shows the mean of any given data set.
Answer:
D
Step-by-step explanation:
f(x) = 3x3
3.3 – 2.02 + 4x - 5
g(x) = 6x - 7
Find (f + g)(x).
Answer:
C) (f+g)(x)= 3x^3-2x^2+10x-12
(b)
The Cartesian coordinates of a point are given.
(1, -5)
(i) Find polar coordinates (r, 0) of the point, where r> 0 and 0 = 0 < 2.
(r, 0) =
(
(ii) Find polar coordinates (r, 0) of the point, where r < 0 and 0 < theta<2pi.
(r, 0) =
Answer:
Step-by-step explanation:
a) r = √(1² + (-5²)) = √26 = 5.09901...
θ = tan⁻¹(-5/1) = 4.9097... radians
(5.1, 4.9)
b) r = - 5.09901...
θ = 4.9097... - π = 1.76819...
(-5.1, 1.8)
Please help me with this on the image
Answer:
Step-by-step explanation:
a). Given expression in the question is,
[tex]\frac{13822\times 623}{14}[/tex]
Exact value of the expression will be,
[tex]\frac{13822\times 623}{14}=615079[/tex]
b). By using approximations to 1 significant figure,
13822 ≈ 10000
623 ≈ 600
14 ≈ 10
615079 ≈ 60000
Now use the expression,
[tex]\frac{13822\times 623}{14}=\frac{10000\times 600}{10}[/tex]
= 60000
6. (4 points) (a) The edge of a cube was measured to be 6 cm, with a maximum possible error of 0.5 cm. Use a differential to estimate the maximum possible error in computing the volume of the cube. (b) Using a calculator, find the actual error in measuring volume if the radius was really 6.5 cm instead of 6 cm, and find the actual error if the radius was actually 5.5 cm instead of 6 cm. Compare these errors to the answer you got using differentials.
Answer:
A) ± 54 cm^3 ( maximum possible error in volume )
B) i) 58.625 cm^3 ii) 49.625 cm^3
Step-by-step explanation:
A) using differential
edge of cube = 6 cm , maximum possible error = 0.5 cm
∴ side of cube ( x )= ± 0.5 cm
V = volume of cube
dv /dx = d(x)^3 / dx
∴ dv = 3x^2 dx ---- ( 1 )
input values into 1
dv = 3(6)^2 * ( ± 0.5 )
= ± 54 cm^3 ( maximum possible error in volume )
B) Using calculator
actual error in measuring volume when
i) radius = 6.5 cm instead of 6 cm
V1= ( 6.5)^3 = 274.625 , V = ( 6)^3 = 216
actual error = 274.625 - 216 = 58.625 cm^3
ii) radius = 5.5cm instead of 6cm
actual error = 49.625 cm^3
Please help out explanation need it
For this you just look at the sides.
Soh cah toa
This is good to remember.
Sin = opposite/ hypotenuse
Cos= adjacent/ hypotenuse
Tan = opposite/ adjacent
In this case you have TanZ, the side adjacent to the angle is 10 and the opposite to the angle is 24. So tanZ is 24/10 which simplifies to 12/5.
The hypotenuse is always the longest side, but the opposite and adjacent sides can change depending on the angle.
Answer:90 = ... 42 + 48) - 360
Step-by-step explanation:
please answer the question below:
Answer:
It's letter b
Step-by-step explanation:
I hope this help
Bill and Will, starting together, ran a 400-meter race, each running at a constant speed. When Bill crossed the finish line, Will was exactly 20 yards behind Bill. They decide to run the race again, this time Bill starting 20 yards behind the original starting line and each running at his same constant speed as before. This time _______ wins by _______ yards.
Answer: Bill, 1
Step-by-step explanation:
Given
Bill and will run a 400 yard race.
Bill win by 20 yard
Suppose the speed of Bill and Will are [tex]\mathbf{v_b}, \mathbf{v_w}[/tex]
time taken for them is same for the first time
[tex]\Rightarrow t_b=t_w\\\\\Rightarrow \dfrac{400}{v_b}=\dfrac{400-20}{v_w}\\\\\Rightarrow \dfrac{v_b}{v_w}=\dfrac{400}{380}\ or\ \dfrac{20}{19}\\[/tex]
Now Bill starts 20 yards behind the starting line
Ratio of their time to cover the distances is
[tex]\Rightarrow \dfrac{t_b}{t_w}=\dfrac{\dfrac{420}{v_b}}{\dfrac{400}{v_w}}\\\\\Rightarrow \dfrac{t_b}{t_w}=\dfrac{420}{400}\times \dfrac{v_w}{v_b}\\\\\Rightarrow \dfrac{t_b}{t_w}=\dfrac{21}{20}\times \dfrac{19}{20}\\\\\Rightarrow \dfrac{t_b}{t_w}=\dfrac{399}{400}[/tex]
The obtained ratio is less than 1. Thus, the time taken by Bill is less than Will.
For the same time Bill wins
[tex]\therefore \dfrac{v_b\times t}{v_w\times t}=\dfrac{420}{x}\\\\\Rightarrow x=19\times 21\\\Rightarrow x=399\ m[/tex]
Thus, Will has covered only 399 yards.
This time Bill wins by 1 yards.
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Slope 0; through (-5, -1)
Answer:
y = -1
Step-by-step explanation:
Need help please due in 1 hour and 30 mins
Answer:
the answer of that is number C
product of a positive and a negative integer is ___________
Answer:
negative
Step-by-step explanation:
because when positive and negative integers are multiplied it results to a negative answer
If Damien does a job in 21 hours less time than Caitlyn, and they can do the job together in 14 hours, how
long will it take each to do the job alone?
Answer: Damien = 7.5 hours and Caitlyn = 28.5 hours
Step-by-step explanation:
Damien = X -21
Caitlyn = X
2X - 21 = 14
2X = 14 + 21
X = (14+21)/2
X = 7.5
The quinceañera (the young woman being celebrated)
dances the first part of the waltz first with her father, for
about 60 seconds.
She then dances with her padrino (godfather), for about
20 seconds.
She then dances with each of the chambelanes, the
young men she has chosen to accompany her on her
special day, for about 15 seconds each.
Bárbara's quinceañera is coming up, and she has to
choose a song that will be exactly the right length, so that
she is not stuck dancing by herself at the end of the song.
How long should her song be? Show your thinking
mathematically.
Answer:
2 minutes and 5 seconds
Step-by-step explanation:
60+20+15+15+15= 125 Seconds ( 2 minutes and 5 seconds )
I added three fifteens as I don't know the number of chambelanes.
Hope it helps!
Can someone please help
Me
Answer:
$3735
Step-by-step explanation:
2/5 = 8/20
8/20 + 7/20 = 15/20 = 3/4
3/4*4980 = 3735
