Question 1

IT Graduates Salary: The recent average starting salary for new college graduates in IT systems is $47,500. Assume salaries are normally distributed with a standard deviation of $4,500.
-What percent of starting salaries are no more than $42,250?

Accepted Answer

The answer of IT Graduates Salary: The recent average starting...

Question 2

As the degrees of freedom approach infinity, the values of a Student t distribution approach those of a standard normal distribution.

Accepted Answer

A) True 
 B)False

Question 3

Given that Z is a standard normal variable, the variance of Z:

Accepted Answer

A)  is always greater than 2.0. 
B)  is always greater than 1.0. 
C)  is always equal to 1.0. 
D)  cannot assume a specific value.

Question 4

The value of an F distribution with v1 = 6 and v2 = 9 degrees of freedom such that the area to its right is 0.05 is 3.37.

Accepted Answer

A) True 
 B)False

Question 5

Electronics Test: The time it takes a student to finish a electronics test has a uniform distribution between 50 and 70 minutes.
-Find the probability that a student will take no less than 55 minutes to finish the test.

Accepted Answer

The answer of Electronics Test: The time it takes a...

Question 6

In practice, we frequently use a continuous distribution to approximate a discrete one when the number of values the variable can assume is countable but very large.

Accepted Answer

A) True 
 B)False

Question 7

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.
-What is the probability that a patient would have to wait no more than one hour?

Accepted Answer

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

Question 8

The probability that Z is less than-2 is the same as one minus the probability that Z is greater than +2.

Accepted Answer

A) True 
 B)False

Question 9

Lamont took a psychology exam whose mean was 70 with standard deviation 5. He also took a calculus exam whose mean was 80 with standard deviation 10. He scored 85 on both exams. On which exam did he do better compared to the other students who took the exam?

Accepted Answer

A)  He did better on the psychology exam, comparatively speaking. 
B)  He did better on the calculus exam, comparatively speaking. 
C)  He did the same on both exams, relatively speaking. 
D)  Cannot tell without more information.

Question 10

Suppose X has a normal distribution with mean 70 and standard deviation 5. The 50th percentile of X is 70.

Accepted Answer

A) True 
 B)False

Question 11

A(n) ____________________ random variable is one that assumes an uncountable number of possible values.

Accepted Answer

The answer of A(n) ____________________ random variable is one that...

Question 12

The 10th percentile of a Z distribution has 10% of the Z-values lying above it.

Accepted Answer

A) True 
 B)False

Question 13

Most values of a standard normal distribution lie between:

Accepted Answer

A)  0 and 1 
B)  -3 and 3 
C)  0 and 3 
D)  minus infinity and plus infinity

Question 14

The expected value of the Student t distribution is zero.

Accepted Answer

A) True 
 B)False

Question 15

We standardize a random variable by subtracting its ____________________ and dividing by its ____________________.

Accepted Answer

The answer of We standardize a random variable by subtracting...

Question 16

A probability density function shows the probability for each value of X.

Accepted Answer

A) True 
 B)False

Question 17

IT Graduates Salary: The recent average starting salary for new college graduates in IT systems is $47,500. Assume salaries are normally distributed with a standard deviation of $4,500.
-What is the cutoff for the bottom 5% of the salaries?

Accepted Answer

The answer of IT Graduates Salary: The recent average starting...

Question 18

Suppose X has a chi-squared distribution with 10 degrees of freedom. The variance of X is:

Accepted Answer

A)  20 
B)  10 
C)  9 
D)  None of these choices.

Question 19

Calculus Scores: Scores of high school students on a national calculus exam were normally distributed with a mean of 86 and a standard deviation of 4. (Total possible points = 100.)
-What is the probability that a randomly selected student will have a score of 80 or higher?

Accepted Answer

The answer of Calculus Scores: Scores of high school students...

Question 20

The mean of the standard normal distribution is ____________________ and the standard deviation is ____________________.

Accepted Answer

The answer of The mean of the standard normal distribution...

Exam 7: Continuous Probability Distributions

IT Graduates Salary: The recent average starting salary for new college graduates in IT systems is $47,500. Assume salaries are normally distributed with a standard deviation of $4,500. -What percent of starting salaries are no more than $42,250?

As the degrees of freedom approach infinity, the values of a Student t distribution approach those of a standard normal distribution.

Given that Z is a standard normal variable, the variance of Z:

The value of an F distribution with v₁ = 6 and v₂ = 9 degrees of freedom such that the area to its right is 0.05 is 3.37.

Electronics Test: The time it takes a student to finish a electronics test has a uniform distribution between 50 and 70 minutes. -Find the probability that a student will take no less than 55 minutes to finish the test.

In practice, we frequently use a continuous distribution to approximate a discrete one when the number of values the variable can assume is countable but very large.

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. -What is the probability that a patient would have to wait no more than one hour?

The probability that Z is less than-2 is the same as one minus the probability that Z is greater than +2.

Lamont took a psychology exam whose mean was 70 with standard deviation 5. He also took a calculus exam whose mean was 80 with standard deviation 10. He scored 85 on both exams. On which exam did he do better compared to the other students who took the exam?

Suppose X has a normal distribution with mean 70 and standard deviation 5. The 50^th percentile of X is 70.

A(n) ____________________ random variable is one that assumes an uncountable number of possible values.

The 10^th percentile of a Z distribution has 10% of the Z-values lying above it.

Most values of a standard normal distribution lie between:

The expected value of the Student t distribution is zero.

We standardize a random variable by subtracting its and dividing by its .

A probability density function shows the probability for each value of X.

IT Graduates Salary: The recent average starting salary for new college graduates in IT systems is $47,500. Assume salaries are normally distributed with a standard deviation of $4,500. -What is the cutoff for the bottom 5% of the salaries?

Suppose X has a chi-squared distribution with 10 degrees of freedom. The variance of X is:

Calculus Scores: Scores of high school students on a national calculus exam were normally distributed with a mean of 86 and a standard deviation of 4. (Total possible points = 100.) -What is the probability that a randomly selected student will have a score of 80 or higher?

The mean of the standard normal distribution is and the standard deviation is .