Question 1

Which of the following is true for an exponential distribution with parameter λ?

Accepted Answer

A) μ = 1/λ 
B) σ = 1/λ 
C) The Y-intercept of f(x)is λ. 
D) All of these choices are true. 
A) μ = 1/λ 
B) σ = 1/λ 
C) The Y-intercept of f(x)is λ. 
D) All of these choices are true.

Question 2

Waiting Time 
The length of time patients must wait to see a doctor at an emergency room in a large hospital has a uniform distribution between 40 minutes and 3 hours. ​ ​
-{Waiting Time Narrative} What is the probability that a patient would have to wait exactly one hour?

Accepted Answer

The answer of  Waiting Time 
The length of time...

Question 3

Use the t-table to find the following values of t.
a.t.10,9
b.t.10,20
c.t.025,82
d.t.05,196

Accepted Answer

a. 1.383

Question 4

Let X be an exponential random variable with λ = 1.50.Find the following:
a.f(x)
b.The y-intercept of f(x)

Accepted Answer

a. f(x)= 1

Question 5

The value of A such that P(−A ≤ t ≤ A)= 0.95,where the degrees of freedom are 20,is 2.086.

Accepted Answer

A) True 
 B)False

Question 6

Checking Accounts 
A bank has determined that the monthly balances of the checking accounts of its customers are normally distributed with an average balance of $1,200 and a standard deviation of $250. ​ ​
-{Checking Accounts Narrative} What proportion of customers have monthly balances less than $1,000?

Accepted Answer

The answer of Checking Accounts 
A bank has determined that...

Question 7

If X has an exponential distribution with parameter λ,then the mean of X is ______________.

Accepted Answer

The answer of If X has an exponential distribution with...

Question 8

The value of a chi-squared distribution with 5 degrees of freedom such that the area to its left is 0.10 is 1.61.

Accepted Answer

A) True 
 B)False

Question 9

If X has an exponential distribution,its ____________________ is equal to its ____________________.

Accepted Answer

mean; standard devia

Question 10

Repair Time 
The time it takes a technician to fix a telephone problem is exponentially distributed with a mean of 15 minutes. ​ ​
-{Repair Time Narrative} What is the probability that it will take a technician less than 10 minutes to fix a telephone problem?

Accepted Answer

The answer of  Repair Time 
The time it takes...

Question 11

The mean of an exponential random variable is ____________________ the median.

Accepted Answer

The answer of The mean of an exponential random variable...

Question 12

In its standardized form,the normal distribution:

Accepted Answer

A) has a mean of 0 and a standard deviation of 1. 
B) has a mean of 1 and a variance of 0. 
C) has an area equal to 0.5. 
D) cannot be used to approximate discrete probability distributions. 
A) has a mean of 0 and a standard deviation of 1. 
B) has a mean of 1 and a variance of 0. 
C) has an area equal to 0.5. 
D) cannot be used to approximate discrete probability distributions.

Question 13

Which of the following statements is correct regarding the percentile points of the F distribution?

Accepted Answer

A) F0.10,10,20 = 1/F0.90,10,20 
B) F0.90,10,20 = 1/F0.10,20,10 
C) F0.90,10,20 = 1/F0.90,20,10 
D) F0.10,10,20 = 1/F0.10,20,10 
A) F0.10,10,20 = 1/F0.90,10,20 
B) F0.90,10,20 = 1/F0.10,20,10 
C) F0.90,10,20 = 1/F0.90,20,10 
D) F0.10,10,20 = 1/F0.10,20,10

Question 14

If the random variable X is exponentially distributed with parameter λ = 0.05,then the probability P(X < 5)= .2865.

Accepted Answer

A) True 
 B)False

Question 15

Phone Orders
 The L.L.Bean catalog department that receives the majority of its orders by telephone conducted a study to determine how long customers were willing to wait on hold before ordering a product.The length of time was found to be a random variable best approximated by an exponential distribution with a mean equal to 3 minutes.
-{Phone Orders Narrative} Find the time at which 50% of the customers will continue to hold?

Accepted Answer

P(X > x)=

Question 16

A random variable X is standardized by subtracting the mean and dividing by the variance.

Accepted Answer

A) True 
 B)False

Question 17

Truck Salesman 
A used truck salesman in a small town states that,on the average,it takes him 5 days to sell a truck.Assume that the probability distribution of the length of time between sales is exponentially distributed. ​ ​
-{Truck Salesman Narrative} What is the probability that he will have to wait between 6 and 10 days before making another sale?

Accepted Answer

The answer of  Truck Salesman 
A used truck salesman...

Question 18

Suppose f(x)= 1/4 over the range a ≤ x ≤ b,and suppose P(X > 4)= 1/2.What are the values for a and b?

Accepted Answer

A) 0 and 4 
B) 2 and 6 
C) Can be any range of x values whose length (b − a)equals 4. 
D) Cannot answer with the information given. 
A) 0 and 4 
B) 2 and 6 
C) Can be any range of x values whose length (b − a)equals 4. 
D) Cannot answer with the information given.

Question 19

The expected value of the Student t distribution is zero.

Accepted Answer

A) True 
 B)False

Question 20

If Z is a standard normal random variable,find the following probabilities:
a.P(Z ≤ −1.77)
b.P(Z ≥ −1.96)
c.P(0.35 ≤ Z ≤ 0.85)
d.P(−2.88 ≤ Z ≤ −2.15)
e.P(Z ≤ 1.45)

Accepted Answer

a. 0.0384 
b. 0.9750

Exam 8: Continuous Probability Distributions

Which of the following is true for an exponential distribution with parameter λ?

Waiting Time The length of time patients must wait to see a doctor at an emergency room in a large hospital has a uniform distribution between 40 minutes and 3 hours. ​ ​ -{Waiting Time Narrative} What is the probability that a patient would have to wait exactly one hour?

Use the t-table to find the following values of t. a.t.10,9 b.t.10,20 c.t.025,82 d.t.05,196

Let X be an exponential random variable with λ = 1.50.Find the following: a.f(x) b.The y-intercept of f(x)

The value of A such that P(−A ≤ t ≤ A)= 0.95,where the degrees of freedom are 20,is 2.086.

If X has an exponential distribution with parameter λ,then the mean of X is ______________.

The value of a chi-squared distribution with 5 degrees of freedom such that the area to its left is 0.10 is 1.61.

If X has an exponential distribution,its ____________________ is equal to its ____________________.

Repair Time The time it takes a technician to fix a telephone problem is exponentially distributed with a mean of 15 minutes. ​ ​ -{Repair Time Narrative} What is the probability that it will take a technician less than 10 minutes to fix a telephone problem?

The mean of an exponential random variable is ____________________ the median.

In its standardized form,the normal distribution:

Which of the following statements is correct regarding the percentile points of the F distribution?

If the random variable X is exponentially distributed with parameter λ = 0.05,then the probability P(X < 5)= .2865.

A random variable X is standardized by subtracting the mean and dividing by the variance.

Suppose f(x)= 1/4 over the range a ≤ x ≤ b,and suppose P(X > 4)= 1/2.What are the values for a and b?

The expected value of the Student t distribution is zero.

If Z is a standard normal random variable,find the following probabilities: a.P(Z ≤ −1.77) b.P(Z ≥ −1.96) c.P(0.35 ≤ Z ≤ 0.85) d.P(−2.88 ≤ Z ≤ −2.15) e.P(Z ≤ 1.45)

What Is Statistics

Graphical Descriptive Techniques 1

Graphical Descriptive Techniques 2

Numerical Descriptive Techniques

Data Collection and Sampling

Probability

Random Variables and Discrete Probability Distributions

Sampling Distributions

Introduction to Estimation

Introduction to Hypothesis Testing

Inference About a Population

Inference About Comparing Two Populations

Analysis of Variance

Chi-Squared Tests

Simple Linear Regression and Correlation

Multiple Regression

Model Building

Nonparametric Statistics

Time-Series Analytics and Forecasting

Statistical Process Control

Decision Analysis

Conclusion

Filters

Waiting Time The length of time patients must wait to see a doctor at an emergency room in a large hospital has a uniform distribution between 40 minutes and 3 hours. -{Waiting Time Narrative} What is the probability that a patient would have to wait exactly one hour?

Use the t-table to find the following values of t. a.t_.10,9 b.t_.10,20 c.t_.025,82 d.t_.05,196

If X has an exponential distribution,its is equal to its .

Repair Time The time it takes a technician to fix a telephone problem is exponentially distributed with a mean of 15 minutes. -{Repair Time Narrative} What is the probability that it will take a technician less than 10 minutes to fix a telephone problem?