Question 1

Let z be a normal random variable with mean 0 and standard deviation 1. The 75th percentile of z is ___.

Accepted Answer

A)  0.67 
B)  -1.25 
C)  0.00 
D)  1.28 
E)  0.50 
A)  0.67 
B)  -1.25 
C)  0.00 
D)  1.28 
E)  0.50

Question 2

Completion time (from start to finish) of a building remodeling project is normally distributed with a mean of 200 work-days and a standard deviation of 10 work-days. To be 99% sure that we will $\textbf{    not     }$  be late in completing the project, we should request a completion time of ___ work-days.

Accepted Answer

A)  211 
B)  207 
C)  223 
D)  200 
E)  250 
A)  211 
B)  207 
C)  223 
D)  200 
E)  250

Question 3

Suppose the mean time to fill a routine prescription at a local pharmacy is 35 minutes based on the time the physician places the order to the time it is dispensed. Assume the standard deviation is 11 minutes and the z score is 0. What is x?

Accepted Answer

A)  -35.0 
B)  0.0 
C)  70.0 
D)  35.0 
E)  -1.0 
A)  -35.0 
B)  0.0 
C)  70.0 
D)  35.0 
E)  -1.0

Question 4

In a standard normal distribution, if the area under curve to the right of a z-value is 0.10, then the area to the left of the same z-value is -0.10.

Accepted Answer

A) True 
 B)False

Question 5

If x is continuously distributed over the interval 8 to 12, inclusively (8 $\le$ x $\le$ 12), then the probability, P(13 $\le$ x $\le$ 15), is ___.

Accepted Answer

A)  0.250 
B)  0.500 
C)  0.375 
D)  0.000 
E)  1.000 
A)  0.250 
B)  0.500 
C)  0.375 
D)  0.000 
E)  1.000

Question 6

The area to the left of the mean in any normal distribution is equal to ___.

Accepted Answer

A)  the mean 
B)  1 
C)  the variance 
D)  0.5 
E)  -0.5 
A)  the mean 
B)  1 
C)  the variance 
D)  0.5 
E)  -0.5

Question 7

Suppose you are working with a data set that is normally distributed with a mean of 400 and a standard deviation of 20. Determine the value of x such that 60% of the values are greater than x.

Accepted Answer

A)  404.5 
B)  395.5 
C)  405.0 
D)  395.0 
E)  415.0 
A)  404.5 
B)  395.5 
C)  405.0 
D)  395.0 
E)  415.0

Question 8

The normal distribution is an example of ___.

Accepted Answer

A)  a discrete distribution 
B)  a continuous distribution 
C)  a bimodal distribution 
D)  an exponential distribution 
E)  a binomial distribution 
A)  a discrete distribution 
B)  a continuous distribution 
C)  a bimodal distribution 
D)  an exponential distribution 
E)  a binomial distribution

Question 9

Completion time (from start to finish) of a building remodeling project is normally distributed with a mean of 200 work-days and a standard deviation of 10 work-days. The probability that the project will be completed within 185 work-days is ___.

Accepted Answer

A)  0.0668 
B)  0.4332 
C)  0.5000 
D)  0.9332 
E)  0.9950 
A)  0.0668 
B)  0.4332 
C)  0.5000 
D)  0.9332 
E)  0.9950

Question 10

The area under the standard normal distribution between -1 and 1 is twice the area between 0 and 1.

Accepted Answer

A) True 
 B)False

Question 11

A uniform continuous distribution is also referred to as a rectangular distribution.

Accepted Answer

A) True 
 B)False

Question 12

The total area underneath any normal curve is equal to ___.

Accepted Answer

A)  the mean 
B)  one 
C)  the variance 
D)  the coefficient of variation 
E)  the standard deviation 
A)  the mean 
B)  one 
C)  the variance 
D)  the coefficient of variation 
E)  the standard deviation

Question 13

If x, the time (in minutes) to complete an change job at certain auto service station, is uniformly distributed over the interval 20 to 30, inclusively (20 $\le$  x $\le$  30), then the probability that an oil change job will be completed 24 minutes or more, i.e., P(x $\geq$ 24) is ___.

Accepted Answer

A)  0.100 
B)  0.000 
C)  0.333 
D)  0.600 
E)  1.000 
A)  0.100 
B)  0.000 
C)  0.333 
D)  0.600 
E)  1.000

Question 14

Let z be a normal random variable with mean 0 and standard deviation 1. What is P(z > -1.1)?

Accepted Answer

A)  0.36432 
B)  0.8643 
C)  0.1357 
D)  -0.1357 
E)  -0.8643 
A)  0.36432 
B)  0.8643 
C)  0.1357 
D)  -0.1357 
E)  -0.8643

Question 15

If x is continuously uniformly distributed over the interval 8 to 12, inclusively (8 $\le$  x $\le$  12), then P(x $\geq$ 10) is ___.

Accepted Answer

A)  0.750 
B)  0.000 
C)  0.333 
D)  0.500 
E)  0.900 
A)  0.750 
B)  0.000 
C)  0.333 
D)  0.500 
E)  0.900

Question 16

Since a normal distribution curve extends from minus infinity to plus infinity, the area under the curve is infinity.

Accepted Answer

A) True 
 B)False

Question 17

A z score is the number of standard deviations that a value of a random variable is above or below the mean.

Accepted Answer

A) True 
 B)False

Question 18

Within a range of z scores from -1 to +1, you can expect to find ___ per cent of the values in a normal distribution.

Accepted Answer

A)  95 
B)  99 
C)  68 
D)  34 
E)  100 
A)  95 
B)  99 
C)  68 
D)  34 
E)  100

Question 19

If x, the time (in minutes) to complete an oil change job at certain auto service station, is uniformly distributed over the interval 20 to 30, inclusively (20 $\le$  x $\le$  30), then the mean of this distribution is ___.

Accepted Answer

A)  50 
B)  25 
C)  10 
D)  15 
E)  5 
A)  50 
B)  25 
C)  10 
D)  15 
E)  5

Question 20

Let z be a normal random variable with mean 0 and standard deviation 1. What is P(z < -2.1)?

Accepted Answer

A)  0.4821 
B)  -0.4821 
C)  0.9821 
D)  0.0179 
E)  -0.0179 
A)  0.4821 
B)  -0.4821 
C)  0.9821 
D)  0.0179 
E)  -0.0179

Let z be a normal random variable with mean 0 and standard deviation 1. The 75^th percentile of z is ___.

Completion time (from start to finish) of a building remodeling project is normally distributed with a mean of 200 work-days and a standard deviation of 10 work-days. To be 99% sure that we will $\textbf{ not }$ be late in completing the project, we should request a completion time of ___ work-days.

Suppose the mean time to fill a routine prescription at a local pharmacy is 35 minutes based on the time the physician places the order to the time it is dispensed. Assume the standard deviation is 11 minutes and the z score is 0. What is x?

In a standard normal distribution, if the area under curve to the right of a z-value is 0.10, then the area to the left of the same z-value is -0.10.

If x is continuously distributed over the interval 8 to 12, inclusively (8 $\le$ x $\le$ 12), then the probability, P(13 $\le$ x $\le$ 15), is ___.

The area to the left of the mean in any normal distribution is equal to ___.

Suppose you are working with a data set that is normally distributed with a mean of 400 and a standard deviation of 20. Determine the value of x such that 60% of the values are greater than x.

The normal distribution is an example of ___.

Completion time (from start to finish) of a building remodeling project is normally distributed with a mean of 200 work-days and a standard deviation of 10 work-days. The probability that the project will be completed within 185 work-days is ___.

The area under the standard normal distribution between -1 and 1 is twice the area between 0 and 1.

A uniform continuous distribution is also referred to as a rectangular distribution.

The total area underneath any normal curve is equal to ___.

If x, the time (in minutes) to complete an change job at certain auto service station, is uniformly distributed over the interval 20 to 30, inclusively (20 $\le$ x $\le$ 30), then the probability that an oil change job will be completed 24 minutes or more, i.e., P(x $\geq$ 24) is ___.

Let z be a normal random variable with mean 0 and standard deviation 1. What is P(z > -1.1)?

If x is continuously uniformly distributed over the interval 8 to 12, inclusively (8 $\le$ x $\le$ 12), then P(x $\geq$ 10) is ___.

Since a normal distribution curve extends from minus infinity to plus infinity, the area under the curve is infinity.

A z score is the number of standard deviations that a value of a random variable is above or below the mean.

Within a range of z scores from -1 to +1, you can expect to find ___ per cent of the values in a normal distribution.

If x, the time (in minutes) to complete an oil change job at certain auto service station, is uniformly distributed over the interval 20 to 30, inclusively (20 $\le$ x $\le$ 30), then the mean of this distribution is ___.

Let z be a normal random variable with mean 0 and standard deviation 1. What is P(z < -2.1)?

Introduction to Statistics

Organizing and Visualizing Data

Descriptive Statistics

Gathering Data

Probability

Decision Analysis and Expected Value

Discrete Probability Distributions

Sampling Distributions

Confidence Intervals

Hypothesis Testing for Single Populations

Hypothesis Testing for Two Populations

Analysis of Variance Anova

Linear Correlation and Simple Linear Regression Analysis

Categorical Versus Categorical: Tests

Filters

Exam 8: Continuous Distributions

Let z be a normal random variable with mean 0 and standard deviation 1. The 75th percentile of z is ___.

Suppose the mean time to fill a routine prescription at a local pharmacy is 35 minutes based on the time the physician places the order to the time it is dispensed. Assume the standard deviation is 11 minutes and the z score is 0. What is x?

In a standard normal distribution, if the area under curve to the right of a z-value is 0.10, then the area to the left of the same z-value is -0.10.

If x is continuously distributed over the interval 8 to 12, inclusively (8 ≤\le≤ x ≤\le≤ 12), then the probability, P(13 ≤\le≤ x ≤\le≤ 15), is ___.

The area to the left of the mean in any normal distribution is equal to ___.

Suppose you are working with a data set that is normally distributed with a mean of 400 and a standard deviation of 20. Determine the value of x such that 60% of the values are greater than x.

The normal distribution is an example of ___.

Completion time (from start to finish) of a building remodeling project is normally distributed with a mean of 200 work-days and a standard deviation of 10 work-days. The probability that the project will be completed within 185 work-days is ___.

The area under the standard normal distribution between -1 and 1 is twice the area between 0 and 1.

A uniform continuous distribution is also referred to as a rectangular distribution.

The total area underneath any normal curve is equal to ___.

If x, the time (in minutes) to complete an change job at certain auto service station, is uniformly distributed over the interval 20 to 30, inclusively (20 ≤\le≤ x ≤\le≤ 30), then the probability that an oil change job will be completed 24 minutes or more, i.e., P(x ≥\geq≥ 24) is ___.

Let z be a normal random variable with mean 0 and standard deviation 1. What is P(z > -1.1)?

If x is continuously uniformly distributed over the interval 8 to 12, inclusively (8 ≤\le≤ x ≤\le≤ 12), then P(x ≥\geq≥ 10) is ___.

Since a normal distribution curve extends from minus infinity to plus infinity, the area under the curve is infinity.

A z score is the number of standard deviations that a value of a random variable is above or below the mean.

Within a range of z scores from -1 to +1, you can expect to find ___ per cent of the values in a normal distribution.

If x, the time (in minutes) to complete an oil change job at certain auto service station, is uniformly distributed over the interval 20 to 30, inclusively (20 ≤\le≤ x ≤\le≤ 30), then the mean of this distribution is ___.

Let z be a normal random variable with mean 0 and standard deviation 1. What is P(z < -2.1)?

Introduction to Statistics

Organizing and Visualizing Data

Descriptive Statistics

Gathering Data

Probability

Decision Analysis and Expected Value

Discrete Probability Distributions

Sampling Distributions

Confidence Intervals

Hypothesis Testing for Single Populations

Hypothesis Testing for Two Populations

Analysis of Variance Anova

Linear Correlation and Simple Linear Regression Analysis

Categorical Versus Categorical: Tests

Filters

Let z be a normal random variable with mean 0 and standard deviation 1. The 75^th percentile of z is ___.

If x is continuously distributed over the interval 8 to 12, inclusively (8 $\le$ x $\le$ 12), then the probability, P(13 $\le$ x $\le$ 15), is ___.

If x, the time (in minutes) to complete an change job at certain auto service station, is uniformly distributed over the interval 20 to 30, inclusively (20 $\le$ x $\le$ 30), then the probability that an oil change job will be completed 24 minutes or more, i.e., P(x $\geq$ 24) is ___.

If x is continuously uniformly distributed over the interval 8 to 12, inclusively (8 $\le$ x $\le$ 12), then P(x $\geq$ 10) is ___.

If x, the time (in minutes) to complete an oil change job at certain auto service station, is uniformly distributed over the interval 20 to 30, inclusively (20 $\le$ x $\le$ 30), then the mean of this distribution is ___.