Question 1

If z is a standard normal variable, find the probability.
-The probability that z is less than 1.13

Accepted Answer

A)  0.8907 
B)  0.8485 
C)  0.8708 
D)  0.1292 
A)  0.8907 
B)  0.8485 
C)  0.8708 
D)  0.1292

Question 2

Find the area of the shaded region. The graph depicts the standard normal distribution with mean 0 and standard
deviation 1.
-

Accepted Answer

A)  0.8812 
B)  0.9406 
C)  0.1188 
D)  0.0594 
A)  0.8812 
B)  0.9406 
C)  0.1188 
D)  0.0594

Question 3

Solve the problem.
-A poll of 1200 randomly selected students in grades 6 through 8 was conducted and found that 34% enjoy
playing sports. Is the 34% result a statistic or a parameter? Explain.

Accepted Answer

Statistic, because i

Question 4

Solve the problem.
-For women aged 18-24, systolic blood pressures (in mm Hg) are normally distributed with a mean of 114.8 and a standard deviation of 13.1. If 36 women are selected at random from a population of 300 women aged 18-24,
Find the probability that their mean systolic blood pressure will be less than 110 mm Hg. Assume that the
Sampling is done without replacement and use a finite population correction factor with N = 300.

Accepted Answer

A)  0.0096 
B)  0.3483 
C)  0.0146 
D)  0.3557 
A)  0.0096 
B)  0.3483 
C)  0.0146 
D)  0.3557

Question 5

Find the area of the shaded region. The graph depicts the standard normal distribution with mean 0 and standard deviation 1.

Accepted Answer

A)  0.4656 
B)  0.0344 
C)  -0.0344 
D)  0.9656 
A)  0.4656 
B)  0.0344 
C)  -0.0344 
D)  0.9656

Question 6

If z is a standard normal variable, find the probability.
-The probability that z lies between 0.7 and 1.98

Accepted Answer

A)  0.2175 
B)  -0.2181 
C)  1.7341 
D)  0.2181 
A)  0.2175 
B)  -0.2181 
C)  1.7341 
D)  0.2181

Question 7

Estimate the indicated probability by using the normal distribution as an approximation to the binomial distribution.
-With n = 20 and p = 0.60, estimate P(fewer than 8).

Accepted Answer

A)  0.0668 
B)  0.4953 
C)  0.0202 
D)  0.4332 
A)  0.0668 
B)  0.4953 
C)  0.0202 
D)  0.4332

Question 8

If a histogram of a sample of men's ages is skewed, what do you expect to see in the normal quantile plot?

Accepted Answer

A)  Points are following a straight-line pattern. 
B)  Points are not following a straight-line pattern. 
A)  Points are following a straight-line pattern. 
B)  Points are not following a straight-line pattern.

Question 9

Solve the problem.
-Three randomly selected households are surveyed as a pilot project for a larger survey to be conducted later.
The numbers of people in the households are 1, 4, and 8. Consider the values of 1, 4, and 8 to be a population.
Assume that samples of size n = 2 are randomly selected with replacement from the population of 1, 4, and 8.
The nine different samples are as follows: (1, 1), (1, 4), (1, 8), (4, 1), (4, 4), (4, 8), (8, 1), (8, 4), and (8, 8). (i) Find
the standard deviation of each of the nine samples, then summarize the sampling distribution of the standard
deviations in the format of a table representing the probability distribution. (ii) Compare the population
standard deviation to the mean of the sample standard deviations. (iii) Do the sample standard deviations
target the value of the population standard deviation? In general, do standard deviations make good estimators
of population standard deviation? Why or why not?

Accepted Answer

(i)
 . The values are not equa

Question 10

Solve the problem. Round to the nearest tenth unless indicated otherwise.
-Scores on an English test are normally distributed with a mean of 37.3 and a standard deviation of 8. Find the score that separates the top 59% from the bottom 41%

Accepted Answer

A)  39.1 
B)  35.5 
C)  32.6 
D)  42.0 
A)  39.1 
B)  35.5 
C)  32.6 
D)  42.0

Question 11

Solve the problem.
-In a population of 225 women, the heights of the women are normally distributed with a mean of 64.5 inches and a standard deviation of 2.9 inches. If 25 women are selected at random, find the probability that their mean
Height will exceed 66 inches. Assume that the sampling is done without replacement and use a finite population
Correction factor with N = 225.

Accepted Answer

A)  0.3015 
B)  0.0031 
C)  0.0048 
D)  0.2912 
A)  0.3015 
B)  0.0031 
C)  0.0048 
D)  0.2912

Question 12

In one region, the September energy consumption levels for single -family homes are found to be normally distributed with a mean of 1050 kWh and a standard deviation of 218 kWh. For a randomly selected home, find
The probability that the September energy consumption level is between 1100 kWh and 1225 kWh.

Accepted Answer

A)  0.2881 
B)  0.0910 
C)  0.3791 
D)  0.1971 
A)  0.2881 
B)  0.0910 
C)  0.3791 
D)  0.1971

Question 13

The normal distribution has a greater percentage of its area close to the mean and much less in the tails.
-Find the area of the shaded region. The graph depicts IQ scores of adults, and those scores are normally distributed with a mean of 100 and a standard deviation of 15 (as on the Wechsler test).

Accepted Answer

A)  0.4400 
B)  0.7486 
C)  0.6293 
D)  0.8051 
A)  0.4400 
B)  0.7486 
C)  0.6293 
D)  0.8051

Question 14

The number of books sold over the course of the four-day book fair were 194, 197, 247, and 76. Assume that
samples of size 2 are randomly selected with replacement from this population of four values. List the different
possible samples, and find the mean of each of them.

Accepted Answer

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\hline \text

Question 15

Solve the problem.
-Scores on a test have a mean of 67 and $\mathrm { Q } _ { 3 }$ is 83. The scores have a distribution that is approximately normal. Find the standard deviation. Round your answer to the nearest tenth.

Accepted Answer

A)  21.3 
B)  12 
C)  10.7 
D)  23.9 
A)  21.3 
B)  12 
C)  10.7 
D)  23.9

Question 16

Solve the problem.
-Three randomly selected households are surveyed as a pilot project for a larger survey to be conducted later.
The numbers of people in the households are 2, 4, and 8. Consider the values of 2, 4, and 8 to be a population.
Assume that samples of size n = 2 are randomly selected with replacement from the population of 2, 4, and 8.
The nine different samples are as follows: (2, 2), (2, 4), (2, 8), (4, 2), (4, 4), (4, 8), (8, 2), (8, 4), and (8, 8). (i) Find
the variance of each of the nine samples, then summarize the sampling distribution of the variances in the
format of a table representing the probability distribution. (ii) Compare the population variance to the mean of
the sample variances. (iii) Do the sample variances target the value of the population variance? In general, do
variances make good estimators of population variances? Why or why not?

Accepted Answer

(i)
 . The values are equal.
(

Question 17

Solve the problem.
-The annual precipitation amounts in a certain mountain range are normally distributed with a mean of 109 inches, and a standard deviation of 10 inches. What is the probability that the mean annual precipitation during
25 randomly picked years will be less than 111.8 inches?

Accepted Answer

A)  0.0808 
B)  0.5808 
C)  0.9192 
D)  0.4192 
A)  0.0808 
B)  0.5808 
C)  0.9192 
D)  0.4192

Question 18

The Precision Scientific Instrument Company manufactures thermometers that are supposed to give readings of 0°C at the freezing point of water. Tests on a large sample of these thermometers reveal that at the freezing
Point of water, some give readings below 0°C (denoted by negative numbers) and some give readings above
0°C (denoted by positive numbers). Assume that the mean reading is 0°C and the standard deviation of the
Readings is 1.00°C. Also assume that the frequency distribution of errors closely resembles the normal
Distribution. A thermometer is randomly selected and tested. A quality control analyst wants to examine
Thermometers that give readings in the bottom 4%. Find the temperature reading that separates the bottom 4%
From the others.

Accepted Answer

A)  -1.48° 
B)  -1.75° 
C)  -1.89° 
D)  -1.63° 
A)  -1.48° 
B)  -1.75° 
C)  -1.89° 
D)  -1.63°

Question 19

A normal quartile plot is given below for the lifetimes (in hours) of a sample of batteries of a particular brand.
Use the plot to assess the normality of the lifetimes of these batteries. Explain your reasoning.

Accepted Answer

Since the normal quartile plot

Question 20

Solve the problem.
-The probability of more than 44 correct answers

Accepted Answer

A)  The area to the right of 44 
B)  The area to the left of 44.5 
C)  The area to the right of 43.5 
D)  The area to the right of 44.5 
A)  The area to the right of 44 
B)  The area to the left of 44.5 
C)  The area to the right of 43.5 
D)  The area to the right of 44.5

If z is a standard normal variable, find the probability. -The probability that z is less than 1.13

Find the area of the shaded region. The graph depicts the standard normal distribution with mean 0 and standard deviation 1. -

Solve the problem. -A poll of 1200 randomly selected students in grades 6 through 8 was conducted and found that 34% enjoy playing sports. Is the 34% result a statistic or a parameter? Explain.

Find the area of the shaded region. The graph depicts the standard normal distribution with mean 0 and standard deviation 1.

If z is a standard normal variable, find the probability. -The probability that z lies between 0.7 and 1.98

Estimate the indicated probability by using the normal distribution as an approximation to the binomial distribution. -With n = 20 and p = 0.60, estimate P(fewer than 8).

If a histogram of a sample of men's ages is skewed, what do you expect to see in the normal quantile plot?

Solve the problem. Round to the nearest tenth unless indicated otherwise. -Scores on an English test are normally distributed with a mean of 37.3 and a standard deviation of 8. Find the score that separates the top 59% from the bottom 41%

The number of books sold over the course of the four-day book fair were 194, 197, 247, and 76. Assume that samples of size 2 are randomly selected with replacement from this population of four values. List the different possible samples, and find the mean of each of them.

Solve the problem. -Scores on a test have a mean of 67 and $\mathrm { Q } _ { 3 }$ is 83. The scores have a distribution that is approximately normal. Find the standard deviation. Round your answer to the nearest tenth.

Solve the problem. -The annual precipitation amounts in a certain mountain range are normally distributed with a mean of 109 inches, and a standard deviation of 10 inches. What is the probability that the mean annual precipitation during 25 randomly picked years will be less than 111.8 inches?

A normal quartile plot is given below for the lifetimes (in hours) of a sample of batteries of a particular brand. Use the plot to assess the normality of the lifetimes of these batteries. Explain your reasoning.

Solve the problem. -The probability of more than 44 correct answers

Introduction to Statistics

Exploring Data With Tables and Graphs

Describing, Exploring, and Comparing Data

Probability

Discrete Probability Distributions

Estimating Parameters and Determining Sample Sizes

Hypothesis Testing

Inferences From Two Samples

Correlation and Regression

Goodness-Of-Fit and Contingency Tables

Analysis of Variance

Nonparametric Tests

Statistical Process Control

Filters

Exam 6: Normal Probability Distributions

If z is a standard normal variable, find the probability. -The probability that z is less than 1.13

Find the area of the shaded region. The graph depicts the standard normal distribution with mean 0 and standard deviation 1. -

Solve the problem. -A poll of 1200 randomly selected students in grades 6 through 8 was conducted and found that 34% enjoy playing sports. Is the 34% result a statistic or a parameter? Explain.

Find the area of the shaded region. The graph depicts the standard normal distribution with mean 0 and standard deviation 1.

If z is a standard normal variable, find the probability. -The probability that z lies between 0.7 and 1.98

Estimate the indicated probability by using the normal distribution as an approximation to the binomial distribution. -With n = 20 and p = 0.60, estimate P(fewer than 8).

If a histogram of a sample of men's ages is skewed, what do you expect to see in the normal quantile plot?

Solve the problem. Round to the nearest tenth unless indicated otherwise. -Scores on an English test are normally distributed with a mean of 37.3 and a standard deviation of 8. Find the score that separates the top 59% from the bottom 41%

The number of books sold over the course of the four-day book fair were 194, 197, 247, and 76. Assume that samples of size 2 are randomly selected with replacement from this population of four values. List the different possible samples, and find the mean of each of them.

Solve the problem. -Scores on a test have a mean of 67 and Q3\mathrm { Q } _ { 3 }Q3​ is 83. The scores have a distribution that is approximately normal. Find the standard deviation. Round your answer to the nearest tenth.

Solve the problem. -The annual precipitation amounts in a certain mountain range are normally distributed with a mean of 109 inches, and a standard deviation of 10 inches. What is the probability that the mean annual precipitation during 25 randomly picked years will be less than 111.8 inches?

A normal quartile plot is given below for the lifetimes (in hours) of a sample of batteries of a particular brand. Use the plot to assess the normality of the lifetimes of these batteries. Explain your reasoning.

Solve the problem. -The probability of more than 44 correct answers

Introduction to Statistics

Exploring Data With Tables and Graphs

Describing, Exploring, and Comparing Data

Probability

Discrete Probability Distributions

Estimating Parameters and Determining Sample Sizes

Hypothesis Testing

Inferences From Two Samples

Correlation and Regression

Goodness-Of-Fit and Contingency Tables

Analysis of Variance

Nonparametric Tests

Statistical Process Control

Filters

Solve the problem. -Scores on a test have a mean of 67 and $\mathrm { Q } _ { 3 }$ is 83. The scores have a distribution that is approximately normal. Find the standard deviation. Round your answer to the nearest tenth.