Deck 15: Statistical Evaluation of Data.

Question 1

If a frequency distribution is shown in a bar graph,what scale was used to measure the scores?

A)​nominal only
B)​nominal or ordinal
C)ratio only
D)​interval or ratio

Answer 1

B

Question 2

For scores measured on a nominal scale of measurement (for example,job classification),which measure of central tendency is appropriate?

A)​mean
B)​median
C)mode
D)​standard deviation

Answer 2

C

Question 3

The concept of degrees of freedom is associated with the ____.

A)​mean for a sample
B)​mean for a population
C)variance for a sample
D)​variance for a population

Answer 3

C

Question 4

If a distribution of numerical scores contains one or two extremely high values,compared to the rest of the scores,which measure of central tendency would produce the most representative value?

A)​the mean
B)​the median
C)the mode
D)​the standard deviation

Question 5

If a set of scores has a mean of 45 and a standard deviation of 9,then the scores have a variance of ____.

A)​3
B)​4.5
C)18
D)​81

Question 6

What is the definition of variance?

A)​the sum of the scores divided by the number of scores
B)​the average distance from the mean
C)the square root of the average distance from the mean
D)​the average squared distance from the mean

Question 7

A researcher uses an anonymous survey to investigate the study habits of American college students.Based on the set of 56 surveys that were completed and returned,the researcher finds that these students spend an average of 4.1 hours each week working on course material outside of class.For this study,the average of 4.1 hours is an example of a(n)____.

A)​parameter
B)​statistic
C)population
D)​sample

Question 8

A characteristic,usually a numerical value that describes a sample,is called a ____.

A)​parameter
B)​statistic
C)variable
D)​constant

Question 9

Where is a score of X = 45 located in a distribution with a mean of 40 and a standard deviation of 12?

A)​slightly above average
B)​far above average
C)slightly below average
D)​far below average

Question 10

A researcher is interested in the sleeping habits of students at the local state college.The entire set of students enrolled at the college is an example of a ____.

A)​statistic
B)​parameter
C)sample
D)​population

Question 11

A researcher has measured self-esteem for a sample of 40 first-grade children.The researcher would like to divide the children into two equal‑sized groups consisting of the high self-esteem kids and the low self-esteem kids.Which statistical measure will identify the correct score to serve as the boundary between the high and the low self-esteem groups?

A)​the mean
B)​the median
C)the mode
D)​the standard deviation

Question 12

It is possible for a distribution of scores to have more than one ____.

A)​mean
B)​median
C)mode
D)​range

Question 13

The ages of the children in a summer camp range from 7 to 12 years old.A counselor constructs a frequency distribution graph showing the number of children for each of the six age groups.What kind of graph would be appropriate for this distribution?

A)​a line graph
B)​a polygon
C)a bar graph
D)​a scatter plot

Question 14

Which general category of statistical methods is intended to answer questions about populations by using sample data?

A)​parameters
B)​statistics
C)descriptive statistics
D)​inferential statistics

Question 15

Statistical techniques that summarize,organize,and simplify data are best classified as ____ statistics.

A)​population
B)​sample
C)descriptive
D)​inferential

Question 16

A researcher studies a group of 25 preschool children in order to answer questions about the entire population of preschool children.What general categories of statistical techniques will this researcher be using?

A)​parameters
B)​statistics
C)descriptive statistics
D)​inferential statistics

Question 17

A researcher records the change in weight (gain or loss)during the first semester of college for each individual in a group of 25 freshmen,and calculates the average change in weight.The average is an example of a ____.

A)​parameter
B)​statistic
C)variable
D)​constant

Question 18

A researcher is interested in the sleeping habits of students at the local state college.The average number of hours spent sleeping each night for the entire set of students enrolled at the college is an example of a ____.

A)​statistic
B)​parameter
C)sample
D)​population

Question 19

What kind of frequency distribution graph shows the frequencies as bars that are separated by spaces?

A)​a bar graph
B)​a histogram
C)a polygon
D)​a line graph

Question 20

To construct a frequency distribution graph displaying a set of scores that were measured on an interval or a ratio scale,you should use a ____.

A)​histogram
B)​line graph
C)bar graph
D)​scatter plot

Question 21

A scatter plot shows data points that are widely scattered around a line that slopes down to the right.Which value would be closest to the correlation for these data?​

A)​0.80
B)​0.40
C)0.40
D)​0.80

Question 22

Which statistic estimates the average of all the possible split-half correlations but can only be used when each question has only two response alternatives?

A)​the Spearman-Brown formula
B)​the Kuder-Richardson formula 20
C)Cronbach's alpha
D)​Cohen's kappa

Question 23

A Type II error means that a researcher has ____.

A)​falsely concluded that a treatment has an effect
B)​correctly concluded that a treatment has no effect
C)falsely concluded that a treatment has no effect
D)​correctly concluded that a treatment has an effect

Question 24

By convention,it has been determined that alpha levels should be set no larger than ____.

A)​.50
B)​.10
C).05
D)​.01

Question 25

If a sample is selected from a population,the sample mean is essentially guaranteed to be different from the population mean.In general,the naturally occurring difference between a sample statistic and the corresponding population parameter is called ____.

A)​type I error
B)​type II error
C)sampling error
D)​inferential error

Question 26

Values such as Cohen's d or r2 (the percentage of variance accounted for)are used to measure ____.

A)​the validity of a hypothesis test
B)​the risk of committing a type I error
C)the size of a treatment effect or the strength of a correlation
D)​the level of significance

Question 27

Under what circumstances is a very small treatment effect still likely to be statistically significant?

A)​if the sample size is small and the sample variance is small
B)​if the sample size is small and the sample variance is large
C)if the sample size is large and the sample variance is small
D)​if the sample size is large and the sample variance is large

Question 28

Which combination of factors is most likely to result in a significant outcome for a hypothesis test?

A)​a small sample size and a small variance
B)​a small sample size and a large variance
C)a large sample size and a small variance
D)​a large sample size and a large variance

Question 29

If the data in a scatter plot form a nearly perfect circle,the Pearson correlation would be approximately ____.

A)​+0.8 or +0.9
B)​-0.8 or -0.9
C)1.00
D)​zero

Question 30

What outcome is likely to occur for a hypothesis test evaluating a treatment that has a very large and robust effect?

A)​a Type I error
B)​a Type II error
C)correctly rejecting the null hypothesis
D)​correctly failing to reject the null hypothesis

Question 31

A researcher reports a significant correlation using an alpha level of .01.In this situation,the probability that the researcher is making a ____.

A)​Type I error is p > .01
B)​Type I error is p < .01
C)Type II error is p > .01
D)​Type II error is p < .01.

Question 32

What would the scatter plot show for data that produce a Pearson correlation of r = +.88?

A)​points clustered close to a line that slopes up to the right
B)​points clustered close to a line that slopes down to the right
C)points widely scattered around a line that slopes up to the right
D)​points widely scattered around a line that slopes down to the right

Question 33

In a hypothesis test,standard error measures ____.​

A)​the size of the treatment effect
B)​variability for the sample data
C)the likelihood of a Type I or Type II error
D)​the amount of difference expected just by chance

Question 34

Calculating the percentage of agreement between two observers ____.​

A)​tends to overestimate the true level of agreement
B)​tends to underestimate the true level of agreement
C)is simply an inaccurate method for measuring inter-rater reliability
D)produces an accurate measure of inter-rater reliability without any need for correction

Question 35

A Type I error means that a researcher has ____.

A)​falsely concluded that a treatment has an effect
B)​correctly concluded that a treatment has no effect
C)falsely concluded that a treatment has no effect
D)​correctly concluded that a treatment has an effect

Question 36

The most commonly used descriptive statistics for a set of numerical scores are the mean and the ____.

A)​range
B)​standard deviation
C)mode
D)​median

Question 37

What problem is Cohen's kappa intended to correct?​

A)​Split-half reliability tends to underestimate the true reliability of the full test.
B)Split-half reliability tends to overestimate the true reliability of the full test.
C)The simple percentage of agreement tends to underestimate the true level of agreement between two observers.
D)​The simple percentage of agreement tends to overestimate the true level of agreement between two observers.

Question 38

Which statistic was developed to correct problems with inter-rater reliability?​

A)​Cohen's kappa
B)​Cronbach's alpha
C)Kuder-Richardson formula 20
D)​Spearman-Brown formula

Question 39

One category of data is obtained by measuring two different variables for each individual in a single group of participants.What statistics are most commonly used for data in this category?

A)​descriptive statistics
B)​t tests or analysis of variance
C)correlations or chi-square tests
D)​analysis of variance or chi-square tests

Question 40

One category of data is obtained by measuring one variable for each individual in a single group of participants.What statistics are most commonly used for data in this category?

A)​descriptive statistics
B)​t tests or analysis of variance
C)correlations or chi-square tests
D)​analysis of variance or chi-square tests

Question 41

The goal of descriptive statistics is to simplify,summarize,and organize data.​

Question 42

In a frequency distribution graph,the frequencies are listed on the vertical axis.

Question 43

The median is the most commonly used measure of central tendency.

Question 44

In a distribution with a mean of M = 76 and a standard deviation of SD = 7,a score of 91 would be considered an extreme value.

Question 45

In general,a correlation obtained from a large sample is more likely to be significant than a correlation obtained from a small sample.

Question 46

Without some correction,the percentage of agreement between two observers will tend to overestimate the true level of inter-rater reliability.

Question 47

It is always possible that patterns observed in sample data do not accurately represent patterns in the population.​

Question 48

Without some correction,such as the Spearman-Brown formula,a correlation measuring split-half reliability will tend to overestimate the reliability for the full test.​

Question 49

For data that consist of two or more groups of scores with each score a numerical value measuring the same variable,the most common statistics are those that measure and evaluate the mean differences between groups.

Question 50

A researcher records the average age for a group of 25 preschool children selected to participate in a research study.The average age is an example of a statistic.

Question 51

A summary value,usually numerical,that describes a sample is called a parameter.

Question 52

The mode is the best way to measure central tendency for data from a nominal scale of measurement.

Question 53

A negative correlation means that as the X values decrease,the Y values also tend to decrease.

Question 54

A Type I error means that the hypothesis test has failed to detect a real treatment effect.

Question 55

In general,a sample with large variance is more likely to produce a significant result than a sample with small variance.

Question 56

The goal of a hypothesis test is to demonstrate that the patterns observed in the sample data represent real patterns in the population and are not simply due to chance or sampling error.​

Question 57

In a distribution with a mean of M = 36 and a standard deviation of SD = 8,a score of 40 would be considered an extreme value.

Question 58

A researcher reports a significant correlation using an alpha level of .01.The probability that the researcher is making a Type I error is p < .01.

Question 59

One concern with measuring split-half reliability is that many different correlations are possible depending on how you decide to split the test items in half.

Question 60

When a research report demonstrates a significant treatment effect at the .05 level,you can be more confident that the effect is real than if the researcher had reported a significant effect with an alpha level of only .01.

Question 61

Describe the general purpose for descriptive statistical techniques and for inferential statistical techniques.

Question 62

Describe what is measured by the mean and what is measured by the standard deviation for a set of scores.Describe the set of scores in a sample with a mean of M = 40 and a standard deviation of SD = 4.(Where are most of the scores located? Where are they centered? What range of values do they cover?)​

Question 63

Identify the two basic concerns with using a correlation to measure split-half reliability and explain how these concerns are addressed by Spearman-Brown,K-R 20,and Cronbach's alpha.

Question 64

Identify the basic concern with using the percentage of agreement as a measure of inter-rater reliability and explain how this concern is addressed by Cohen's kappa.

Question 65

Explain the concept of statistical significance.Be sure that the concept of an alpha level in included in your explanation.

Question 66

Identify the purpose for a hypothesis test and briefly explain how a hypothesis test accomplishes its purpose.​

Question 67

Explain why a measure of effect size is recommended to accompany the result from a hypothesis test.