Question 1

Approximately what percentage of scores fall within one standard deviation of the mean?

Accepted Answer

A)  16 
B)  34 
C)  68 
D)  98 
A)  16 
B)  34 
C)  68 
D)  98 C

Question 2

Lucille took the same exam, but received a 78 on it. What was her approximate percentile rank?

Accepted Answer

A)  78th 
B)  16th 
C)  58th 
D)  84th 
A)  78th 
B)  16th 
C)  58th 
D)  84th B

Question 3

A leptokurtic distribution of a variable:

Accepted Answer

A)  is bell-shaped. 
B)  is totally flat. 
C)  has a steep peak. 
D)  is not symmetrical. 
A)  is bell-shaped. 
B)  is totally flat. 
C)  has a steep peak. 
D)  is not symmetrical. C

Question 4

When statisticians refer to the distribution of a variable as "skewed," they mean that a frequency polygon for the variable:

Accepted Answer

A)  would not be bell-shaped. 
B)  would contain one or more outliers. 
C)  would not be symmetrical 
D)  all of the above 
A)  would not be bell-shaped. 
B)  would contain one or more outliers. 
C)  would not be symmetrical 
D)  all of the above

Question 5

A z-score is:

Accepted Answer

A)  the highest value that a variable can assume. 
B)  the value of a variable that falls at +3 standard deviations from the mean. 
C)  a raw score expressed in units of standard deviation. 
D)  another name for an outlier. 
A)  the highest value that a variable can assume. 
B)  the value of a variable that falls at +3 standard deviations from the mean. 
C)  a raw score expressed in units of standard deviation. 
D)  another name for an outlier.

Question 6

If the research sample contained 500 students, approximately how many had 21 or fewer friends?

Accepted Answer

A)  7 
B)  467 
C)  21 
D)  33 
A)  7 
B)  467 
C)  21 
D)  33

Question 7

One hundred students took a statistics mid-term exam. The scores formed a normal distribution with a mean of 84 and a standard deviation of 6. Elice's grade was a 92. What was her approximate percentile rank?

Accepted Answer

A)  91st 
B)  9th 
C)  59th 
D)  84th 
A)  91st 
B)  9th 
C)  59th 
D)  84th

Question 8

In a research sample of high school students, the variable "number of MySpace friends" formed a normal distribution with a mean of 45 and a standard deviation of 16. Valentina had 53 friends. What was her approximate percentile rank?

Accepted Answer

A)  31st 
B)  53rd 
C)  69th 
D)  49th 
A)  31st 
B)  53rd 
C)  69th 
D)  49th

Question 9

In the standard normal distribution:

Accepted Answer

A)  the curve is symmetrical 
B)  the mean, the median, and the mode all occur at the same point. 
C)  the curve approaches, but does not touch the x-axis. 
D)  all of the above 
A)  the curve is symmetrical 
B)  the mean, the median, and the mode all occur at the same point. 
C)  the curve approaches, but does not touch the x-axis. 
D)  all of the above

Question 10

What does it mean when we say that a measurement instrument such as the SAT is a standardized test?

Accepted Answer

A)  The scores on it tend to form a standard normal distribution. 
B)  Everyone receives about the same score on the test. 
C)  The test provides a valid measurement of some variable. 
D)  The test always contains the same questions in the same sequence. 
A)  The scores on it tend to form a standard normal distribution. 
B)  Everyone receives about the same score on the test. 
C)  The test provides a valid measurement of some variable. 
D)  The test always contains the same questions in the same sequence.

Question 11

Approximately what percentage of scores of a normal distribution fall below -2 standard deviations?

Accepted Answer

A)  48% 
B)  98% 
C)  2% 
D)  16% 
A)  48% 
B)  98% 
C)  2% 
D)  16%

Question 12

Which of the following z-scores would fall at the lowest percentile?

Accepted Answer

A)  2.00 
B)  0.00 
C)  -1.35 
D)  1.35 
A)  2.00 
B)  0.00 
C)  -1.35 
D)  1.35

Approximately what percentage of scores fall within one standard deviation of the mean?

Lucille took the same exam, but received a 78 on it. What was her approximate percentile rank?

A leptokurtic distribution of a variable:

When statisticians refer to the distribution of a variable as "skewed," they mean that a frequency polygon for the variable:

A z-score is:

If the research sample contained 500 students, approximately how many had 21 or fewer friends?

One hundred students took a statistics mid-term exam. The scores formed a normal distribution with a mean of 84 and a standard deviation of 6. Elice's grade was a 92. What was her approximate percentile rank?

In a research sample of high school students, the variable "number of MySpace friends" formed a normal distribution with a mean of 45 and a standard deviation of 16. Valentina had 53 friends. What was her approximate percentile rank?

In the standard normal distribution:

What does it mean when we say that a measurement instrument such as the SAT is a standardized test?

Approximately what percentage of scores of a normal distribution fall below -2 standard deviations?

Which of the following z-scores would fall at the lowest percentile?

Introduction

Frequency Distributions and Graphs

Measures of Central Tendency and Variability

Hypothesis Testing: Basic Principles

Sampling Distributions, Rejection Regions, and Statistical Test Selection

T Tests and Analysis of Variance

The Chi-Square Test of Association Between Variables

Correlation Analyses

Regression Analyses

Other Ways That Statistical Analyses Contribute to Evidence-Based Practice

Filters

Exam 4: Normal Distributions

Approximately what percentage of scores fall within one standard deviation of the mean?

Lucille took the same exam, but received a 78 on it. What was her approximate percentile rank?

A leptokurtic distribution of a variable:

When statisticians refer to the distribution of a variable as "skewed," they mean that a frequency polygon for the variable:

A z-score is:

If the research sample contained 500 students, approximately how many had 21 or fewer friends?

One hundred students took a statistics mid-term exam. The scores formed a normal distribution with a mean of 84 and a standard deviation of 6. Elice's grade was a 92. What was her approximate percentile rank?

In a research sample of high school students, the variable "number of MySpace friends" formed a normal distribution with a mean of 45 and a standard deviation of 16. Valentina had 53 friends. What was her approximate percentile rank?

In the standard normal distribution:

What does it mean when we say that a measurement instrument such as the SAT is a standardized test?

Approximately what percentage of scores of a normal distribution fall below -2 standard deviations?

Which of the following z-scores would fall at the lowest percentile?

Introduction

Frequency Distributions and Graphs

Measures of Central Tendency and Variability

Hypothesis Testing: Basic Principles

Sampling Distributions, Rejection Regions, and Statistical Test Selection

T Tests and Analysis of Variance

The Chi-Square Test of Association Between Variables

Correlation Analyses

Regression Analyses

Other Ways That Statistical Analyses Contribute to Evidence-Based Practice

Filters