Statistics for Social Science

For the frequency distribution in Table 2-1, what is the proportion associated with X = 3? Table 2-1 X f 5 2 4 4 3 1 2 3

0.10

For the distribution of quiz scores in Table 2-2, How many individuals had a score of X = 2? Table 2-2 X f 5 6 4 5 3 5 2 3 1 2

3

For a perfectly symmetrical distribution with µ=30, what is the value of the median?

30

For a perfectly symmetrical distribution with µ=30, what is the value of the mode?

30

For the frequency distribution in Table 2-1, what is the value of ƩX? Table 2-1 X f 5 2 4 4 3 1 2 3

35

What is the value of ƩX² for the following scores? Scores: 3, 0, 5, 2

38

In a grouped frequency distribution one interval is listed as 50-59. Assuming that the scores are measuring a continuous variable, what are the real limits of this interval? X f 20-25 2 15-19 5 10-14 4 5-9 1

49.5 and 59.5

A population of N = 6 scores has ƩX=30. What is the population mean?

5

A set of N = 10 scores has a mean of µ=50. If 20 points are added to one of the scores, what is the new value for the population mean?

52

What is the value of the median for the following set of scores? Scores:1, 3, 4, 6, 7, 8, 12, 23

6.5

A sample of n = 20 scores ranges from a high of X = 9 to a low of X = 3. If these scores are placed in a frequency distribution table, how many X values will be listed in the first column?

7

For the distribution in Table 2-3, how many people had scores greater than X = 14? X f 20-25 2 15-19 5 10-14 4 5-9 1

7

One sample has n = 4 scores and M = 10. A second sample has n = 6 scores and M = 5. If the two samples are combined, then what is the mean for the combined sample?

70/10 = 7

What is the first step to be performed in the following mathematical expression? (ƩX)²

Add the scores.

A sample of n = 4 scores has a mean of M = 8. If one new score with a value of X = 3 is added to the sample, what will be the value for the new mean?

M = 7

For the frequency distribution in Table 2-1, how many individual scores are in the entire set? Table 2-1 X f 5 2 4 4 3 1 2 3

N = 10

A population with a mean of µ=8 has ƩX=40. How many scores are in the population?

N=5

A population with a mean of µ=6 has ƩX=42. How many scores are in the population?

N=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 set of 56 students who returned surveys is an example of a ____.

Sample

A sample has a mean of M = 72. If one person with a score of X = 58 is removed from the sample, what effect will it have on the sample mean?

The sample mean will increase.

A sample of n = 5 scores has a mean of M = 8. One new score is added to the sample and the new mean is calculated to be M = 9. What is the value of new score?

X = 14

If the following distribution was shown in a histogram, the bar above the 15-19 interval would reach from ____ to ____. Table 2-3 X f 20-25 2 15-19 5 10-14 4 5-9 1

X = 14.5 to X = 19.5

A population of N = 10 scores has a mean of µ=6. After one score is removed, the mean is found to be M = 5. What is the value of the score that was removed?

X=15

A professor recorded the academic major for each student in an introductory psychology class. If the data are presented in a frequency distribution graph, what type of graph should be used?

a bar graph

The classrooms in the Psychology department are numbered from 100 to 120. A professor records the number of classes held in each room during the fall semester. If these values are presented in a frequency distribution graph, what kind of graph would be appropriate?

a bar graph

For the distribution in Table 2-3, what is the highest score? Table 2-3 X f 20-25 2 15-19 5 10-14 4 5-9 1

cannot be determined

Organizing a set of scores into a table or a graph would be an example of using ____.

descriptive statistics

Statistical methods that organize, summarize, or simplify data are called ____.

descriptive statistics

If it is impossible to divide the existing categories of a variable, then it is an example of a(n) ____ variable.

discrete

For a negatively skewed distribution with a mean of M = 20, what is the value of the median?

greater than 20

In an experiment, the researcher manipulates the ____ variable to create treatment conditions and measures the ____ variable for a group of individuals in each condition.

independent, dependent

After measuring two individuals, a researcher can say that Tom's score is 4 points higher than Bill's. The measurements must come from a(n) ____ scale.

interval or ratio

A distribution is positively skewed. Which is the most probable order, from smallest to largest, for the three measures of central tendency?

mode, median, mean

In a positively skewed distribution, scores with the highest frequencies are ____.

on the left side of the distribution

What frequency distribution graph is appropriate for scores measured on a nominal scale?

only a bar graph

What term is used to describe the shape of a distribution in which the scores pile up on the left-hand side of the graph and taper off to the right?

positively skewed

What additional information is obtained by measuring on an interval scale compared to a ordinal scale?

the size of the differences

A recent study reports that elementary school students who were given a nutritious breakfast each morning had higher test scores than students who did not receive the breakfast. For this study, what is the independent variable?

whether or not a breakfast was given to the students

How would the following mathematical operation be expressed in summation notation? "Subtract 4 points from each score, square the resulting value, then find the sum of the squared numbers."

Ʃ(X-4)²