The lifespan of a car battery averages six years. Suppose the batterylifespan follows an exponential distribution.(a) Find the probability that a randomly selected car battery will lastmore than four years.(b) Find the variance and the 95th percentile of the battery lifespan.(c) Suppose a three-year-old battery is still going strong. (i) Find theprobability the battery will last an additional five years. (ii) Howmuch longer is this battery expected to last

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:

Find out more information about standard​ deviation here:

https://brainly.com/question/25309029

Answer:

Step-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.

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

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

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

Answer:

B:

Step-by-step explanation:

According to theorem, "the angle in a semi-circle is a right angle" So,

<O = 90°

<M = 54

<K = 180-90-54

<OKM = 36°

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.

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.

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

Answer:

x = 12

Step-by-step explanation:

g(x)= 2x-4

g(x)= 20

Therefore,

2x-4 = 20

Bringing -4 to the other side it becomes positive,so..

2x= 20+4

= 24

x =24/2

= 12

Answer:

D

Step-by-step explanation:

An arithmetic sequence is a series of numbers that increases or decreases by a certain quantity every step. A is not an arithmetic sequence, since it alternates between 2 and -2. B is not an arithmetic sequence, since it does not grow constantly in one direction. C is not an arithmetic sequence, but rather a geometric one. D is an arithmetic sequence, decreasing by 3 with each step. Hope this helps!

Answer:

2 wild cards

Step-by-step explanation:

Typical would mean most often

2 wild cards shows up 6 times which is most often

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

Answer:50%

Step-by-step explanation:670/1340 = 1/2 = 50%

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]

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]

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

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!

Answer:

24000

Step-by-step explanation:

because 24000 * 10 =240000

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

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

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]

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!!!

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

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

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

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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#SPJ2

Answer:

the answer is 1/2,a0

Step-by-step explanation:

Answer:

The proportion of the variability seen in math achievement that can be predicted by math attitude is 0.78, the same value as the correlation coefficient.

Step-by-step explanation:

The correlation coefficient r between this two variables is found to be 0.78.

This coefficient can be calculated as:

[tex]r=\dfrac{SSY'}{SSY}[/tex]

where SSY' is the sum of the squares deviation from the mean for the predicted value and SSY is the sum of the squares deviation from the mean for the criterion variable.

Then, the value of the coefficient r is giving the proportion of the variability seen in the criterion value Y that can be explained by the predictor variable X.

Answer:

r=SSY'/SSY

Step-by-step explanation:

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

Answer:

10-19 ⇒ 4

40-49 ⇒ 3

Answer:

10-19: 4 numbers

40-49: 3 numbers

Step-by-step explanation:

10-19: 11, 13, 17, 18 (4 numbers)

40-49: 41, 44, 47 (3 numbers)