Question 1

The normal distribution is often referred to as the bell curve.

Accepted Answer

A) True 
 B)False

Question 2

The difference between a normal distribution and a standard normal distribution is

Accepted Answer

A)  standard normal distributions are more symmetric. 
B)  normal distributions are based on fewer scores. 
C)  standard normal distributions always have a mean of 0 and a standard deviation of 1. 
D)  there is no difference. 
A)  standard normal distributions are more symmetric. 
B)  normal distributions are based on fewer scores. 
C)  standard normal distributions always have a mean of 0 and a standard deviation of 1. 
D)  there is no difference.

Question 3

If we know that the probability for z > 1.5 is .067, then we can say that

Accepted Answer

A)  the probability of exceeding the mean by more than 1.5 standard deviations is .067. 
B)  the probability of being more than 1.5 standard deviations away from the mean is .134. 
C)  86.6% of the scores are less than 1.5 standard deviations from the mean. 
D)  all of the above 
A)  the probability of exceeding the mean by more than 1.5 standard deviations is .067. 
B)  the probability of being more than 1.5 standard deviations away from the mean is .134. 
C)  86.6% of the scores are less than 1.5 standard deviations from the mean. 
D)  all of the above

Question 4

The tables of the standard normal distribution contain only positive values of z . This is because

Accepted Answer

A)  the distribution is symmetric. 
B)  z can take on only positive values. 
C)  we aren't interested in negative values of z . 
D)  probabilities can never be negative. 
A)  the distribution is symmetric. 
B)  z can take on only positive values. 
C)  we aren't interested in negative values of z . 
D)  probabilities can never be negative.

Question 5

There are a few z scores that we use often that are worth remembering. The upper 50%, and 97.5 percent of a normal distribution are cut off by z scores of

Accepted Answer

A)  1.0, and 1.64. 
B)  0.0, and 1.96. 
C)  .50, and .975. 
D)  plus and minus 1.96. 
A)  1.0, and 1.64. 
B)  0.0, and 1.96. 
C)  .50, and .975. 
D)  plus and minus 1.96.

Question 6

If we have data that have been sampled from a population that is normally distributed with a mean of 50 and a standard deviation of 10, we would expect that 95% of our observations would lie in the interval that is approximately

Accepted Answer

A)  30-70. 
B)  35-50. 
C)  45-55. 
D)  70-90. 
A)  30-70. 
B)  35-50. 
C)  45-55. 
D)  70-90.

Question 7

Create a z distribution based on the following data. Explain the process. 
10 20 20 30 30 30 40 40 40 40 50 50 50 60 60 70

Accepted Answer

In order to create a z distribution, you

Question 8

We know that 25% of the class got an A on the last exam, and 30% got a B. What percent got either an A or a B?

Accepted Answer

A)  25% × 30% = 7.5% 
B)  25% + 30 % = 55% 
C)  45% 
D)  We cannot tell from the information that is presented. 
A)  25% × 30% = 7.5% 
B)  25% + 30 % = 55% 
C)  45% 
D)  We cannot tell from the information that is presented.

Question 9

We are interested in what the text calls "probable limits" because

Accepted Answer

A)  we want to know whether a piece of data is unusual. 
B)  we want to have a good idea what kinds of values to expect. 
C)  we might want to know whether values below some specific value are improbable. 
D)  all of the above 
A)  we want to know whether a piece of data is unusual. 
B)  we want to have a good idea what kinds of values to expect. 
C)  we might want to know whether values below some specific value are improbable. 
D)  all of the above

Question 10

A test score of 84 was transformed into a standard score of -1.5. If the standard deviation of test scores was 4, what is the mean of the test scores?

Accepted Answer

A)  78 
B)  80 
C)  90 
D)  88 
A)  78 
B)  80 
C)  90 
D)  88

Question 11

The symbol p is commonly used to refer to

Accepted Answer

A)  any value for the observed variable. 
B)  a value from a standard normal distribution. 
C)  the probability for the occurrence of an observation. 
D)  none of the above 
A)  any value for the observed variable. 
B)  a value from a standard normal distribution. 
C)  the probability for the occurrence of an observation. 
D)  none of the above

Question 12

The formula for calculating the 95% probable limits on an observation is

Accepted Answer

A)  (µ > 1.96 s ) 
B)  ( s + 1.96µ) 
C)  (µ - 1.96 s ) 
D)  (µ ± 1.96 s ) 
A)  (µ > 1.96 s ) 
B)  ( s + 1.96µ) 
C)  (µ - 1.96 s ) 
D)  (µ ± 1.96 s )

Question 13

The ordinate of a normal distribution is often labeled

Accepted Answer

A)  frequency. 
B)  X. 
C)  density. 
D)  proportion. 
A)  frequency. 
B)  X. 
C)  density. 
D)  proportion.

Question 14

A z score refers to the number of standard deviations above or below the mode.

Accepted Answer

A) True 
 B)False

Question 15

Suzie scored in the 95th percentile on the Math portion of the SAT. This means that she scored as high or higher than 95% of the other students who took the test.

Accepted Answer

A) True 
 B)False

Question 16

Stanine scores

Accepted Answer

A)  are badly skewed. 
B)  have a mean of 5 and vary between 1 and 9. 
C)  are always integers. 
D)  both b and c 
A)  are badly skewed. 
B)  have a mean of 5 and vary between 1 and 9. 
C)  are always integers. 
D)  both b and c

Question 17

At a neighboring university, the average salary is also $45,000 and the distribution is normal. If $47,000 has a z score of 1.5, what is the standard deviation?

Accepted Answer

The answer of At a neighboring university, the average salary...

Question 18

The standard normal distribution is a normal distribution with a mean of 0 and a standard deviation of 1.

Accepted Answer

A) True 
 B)False

Question 19

For a normal distribution

Accepted Answer

A)  all of the data points lie within one standard deviation from the mean. 
B)  about 2/3 of the distribution lies within one standard deviation from the mean. 
C)  about 95% of the distribution lies within two standard deviations from the mean. 
D)  both b and c 
A)  all of the data points lie within one standard deviation from the mean. 
B)  about 2/3 of the distribution lies within one standard deviation from the mean. 
C)  about 95% of the distribution lies within two standard deviations from the mean. 
D)  both b and c

Question 20

Most statistical techniques are based on the assumption that the population of observations is not normal.

Accepted Answer

A) True 
 B)False

Exam 6: The Normal Distribution

The normal distribution is often referred to as the bell curve.

The difference between a normal distribution and a standard normal distribution is

If we know that the probability for z > 1.5 is .067, then we can say that

The tables of the standard normal distribution contain only positive values of z . This is because

There are a few z scores that we use often that are worth remembering. The upper 50%, and 97.5 percent of a normal distribution are cut off by z scores of

If we have data that have been sampled from a population that is normally distributed with a mean of 50 and a standard deviation of 10, we would expect that 95% of our observations would lie in the interval that is approximately

Create a z distribution based on the following data. Explain the process. 10 20 20 30 30 30 40 40 40 40 50 50 50 60 60 70

We know that 25% of the class got an A on the last exam, and 30% got a B. What percent got either an A or a B?

We are interested in what the text calls "probable limits" because

A test score of 84 was transformed into a standard score of -1.5. If the standard deviation of test scores was 4, what is the mean of the test scores?

The symbol p is commonly used to refer to

The formula for calculating the 95% probable limits on an observation is

The ordinate of a normal distribution is often labeled

A z score refers to the number of standard deviations above or below the mode.

Suzie scored in the 95th percentile on the Math portion of the SAT. This means that she scored as high or higher than 95% of the other students who took the test.

Stanine scores

At a neighboring university, the average salary is also $45,000 and the distribution is normal. If $47,000 has a z score of 1.5, what is the standard deviation?

The standard normal distribution is a normal distribution with a mean of 0 and a standard deviation of 1.

For a normal distribution

Most statistical techniques are based on the assumption that the population of observations is not normal.

Introduction

Basic Concepts

Displaying Data

Measures of Central Tendency

Measures of Variability

Basic Concepts of Probability

Sampling Distributions and Hypothesis Testing

Correlation

Regression

Multiple Regression

Hypothesis Tests Applied to Means: One Sample

Hypothesis Tests Applied to Means: Two Related Samples

Hypothesis Tests Applied to Means: Two Independent Samples

Power

One-Way Analysis of Variance

Factorial Analysis of Variance

Repeated-Measures Analysis of Variance

Chi-Square

Nonparametric and Resampling Statistical Tests

Meta-Analysis

Filters

Suzie scored in the 95^th percentile on the Math portion of the SAT. This means that she scored as high or higher than 95% of the other students who took the test.