LEARNING CHECKS (Psychological Statistics)

b. statistic

A researcher is interested in the sleeping habits of American college students. A group of 50 students is interviewed, and the researcher finds that these students sleep an average of 6.7 hours per day. For this study, the average of 6.7 hours is an example of a(n) ___________.

a. parameter

b. statistic

c. population

d. sample

c. population

A researcher is curious about the average IQ of registered voters in the state of Florida. The entire group of registered voters in the state is an example of a __________.

a. sample

b. statistic

c. population 1

d. parameter

c. descriptive statistics

Statistical techniques that summarize, organize, and simplify data are classified as __________.

a. population statistics

b. sample statistics

c. descriptive statistics

d. inferential statistics

b. descriptive, inferential

In general, __________ statistical techniques are used to summarize the data from a research study, and __________ statistical techniques are used to determine what conclusions are justified by the results.

a. inferential, descriptive

b. descriptive, inferential

c. sample, population

d. population, sample

d. sampling error

IQ tests are standardized so that the average score is 100 for the entire group of people who take the test each year. However, if you selected a group of 20 people who took the test and computed their average IQ score you probably would not get 100. What statistical concept explains the difference between your mean and the mean for the entire group?

a. statistical error

b. inferential error

c. descriptive error

d. sampling error

c. 2 variables and 1 group

In a correlational study, how many variables are measured for each individual and how many groups of scores are obtained?

a. 1 variable and 1 group

b. 1 variable and 2 groups

c. 2 variables and 1 group

d. 2 variables and 2 groups

c. nonexperimental

A research study comparing alcohol use for college students in the United States and Canada reports that more Canadian students drink but American students drink more (Kuo, Adlaf, Lee, Gliksman, Demers, and Wechsler, 2002). What research design did this study use?

a. correlational

b. experimental

c. nonexperimental

d. noncorrelational

d. the kind of word shouted by the participants

Stephens, Atkins, and Kingston (2009) found that participants were able to tolerate more pain when they shouted their favorite swear words over and over than when they shouted neutral words. For this study, what is the independent variable?

a. the amount of pain tolerated

b. the participants who shouted swear words

c. the participants who shouted neutral words

d. the kind of word shouted by the participants

c. measure and define

An operational definition is used to __________ a hypothetical construct.

a. define

b. measure

c. measure and define

d. None of the other choices is correct.

a. discrete

A researcher studies the factors that determine the number of children that couples decide to have. The variable, number of children, is an example of a __________ variable.

a. discrete

b. continuous

c. nominal

d. ordinal

b. 67.5 and 68.5

When measuring height to the nearest half inch, what are the real limits for a score of 68.0 inches?

a. 67 and 69

b. 67.5 and 68.5

c. 67.75 and 68.75

d. 67.75 and 68.25

a. nominal

The teacher in a communications class asks students to identify their favorite reality television show. The different television shows make up a __________ scale of measurement.

a. nominal

b. ordinal

c. interval

d. ratio

b. the number of scores in a sample

What value is represented by the lowercase letter n?

a. the number of scores in a population

b. the number of scores in a sample

c. the number of values to be added in a summation problem

d. the number of steps in a summation problem

d. 6

What is the value of Σ(X - 2) for the following scores: 6, 2, 4, 2?

a. 12

b. 10

c. 8

d. 6

b. Add the scores.

What is the first step in the calculation of (ΣX)2?

a. Square each score.

b. Add the scores.

c. Subtract 2 points from each score.

d. Add the X - 2 values.

c. 3

For the following frequency distribution, how many individuals had a score of X = 2?

X: 5, 4, 3, 2, 1

f: 1, 2, 4, 3, 2

a. 1

b. 2

c. 3

d. 4

c. 5

The following is a distribution of quiz scores. If a score of X = 2 or lower is failing, then how many individuals failed the quiz?

X: 5, 4, 3, 2, 1

f: 1, 2, 4, 3, 2

a. 2

b. 3

c. 5

d. 9

b. 45

For the following frequency distribution, what is ΣX^2?

X: 4, 3, 2, 1, 0

f: 1, 2, 2, 3, 1

a. 30

b. 45

c. 77

d. (17)^2 = 289

c. 4

For this distribution, how many individuals had scores lower than X = 20?

X: 24-25, 22-23, 20-21, 18-19, 16-17

f: 2, 4, 6, 3, 1

a. 2

b. 3

c. 4

d. cannot be determined

c. 5 points

In a grouped frequency distribution one interval is listed as 20-24. Assuming that the scores are measuring a continuous variable, what is the width of this interval?

a. 3 points

b. 4 points

c. 5 points

d. 54 points

c. 10-14

A set of scores ranges from a high of X = 48 to a low of X = 13. If these scores are placed in a grouped frequency distribution table with an interval width of 5 points, the bottom interval in the table would be _______.

a. 13-18

b. 13-19

c. 10-14

d. 10-15

d. a bar graph

The seminar rooms in the library are identified by letters (A, B, C, and so on). 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. a histogram

b. a polygon

c. a histogram or a polygon

d. a bar graph

a. There are more high scores than there are low scores.

A group of quiz scores ranging from 4-9 are shown in a histogram. If the bars in the histogram gradually increase in height from left to right, what can you conclude about the set of quiz scores?

a. There are more high scores than there are low scores.

b. There are more low scores than there are high scores.

c. The height of the bars always increases as the scores increase.

d. None of the above

b. population

If a frequency distribution graph is drawn as a smooth curve, it is probably showing a ______ distribution.

a. sample

b. population

c. skewed

d. symmetrical

b. positively skewed

A set of scores is presented in a frequency distribution histogram. If the histogram shows a series of bars that tend to decrease in height from left to right, then what is the shape of the distribution?

a. symmetrical

b. positively skewed

c. negatively skewed

d. normal

b. the 80th percentile

In a distribution of exam scores, which of the following would be the highest score?

a. the 20th percentile

b. the 80th percentile

c. a score with a percentile rank of 15%

d. a score with a percentile rank of 75%

d. X = 29.5

Following are three rows from a frequency distribution table. For this distribution, what is the 90th percentile?

X: 30-34, 25-29, 20-24

c% 100%, 90%, 60%

a. X = 24.5

b. X = 25

c. X = 29

d. X = 29.5

c. 29%

Following are three rows from a frequency distribution table. Using interpolation, what is the percentile rank for X = 18?

X: 20-24, 15-19, 10-14

c%: 60%, 35%, 15%

a. 52.5%

b. 30%

c. 29%

d. 25%

d. 51

For the scores shown in the following stem and leaf display, what is the lowest score in the distribution?

9 I 374

8 I 945

7 I 7042

6 I 68

5 I 14

a. 7

b. 15

c. 50

d. 51

d. 4

For the scores shown in the following stem and leaf display, how many people had scores in the 70s?

9 I 374

8 I 945

7 I 7042

6 I 68

5 I 14

a. 1

b. 2

c. 3

d. 4

d. 3

What is the mean for the following sample of scores? Scores: 1, 2, 5, 4

a. 12

b. 6

c. 4

d. 3

b. The sample mean will decrease.

A sample has a mean of M = 45. If one person with a score of X = 53 is removed from the sample, what effect will it have on the sample mean?

a. The sample mean will increase.

b. The sample mean will decrease.

c. The sample mean will remain the same.

d. Cannot be determined from the information given

b. 4

One sample has n = 8 scores and M = 2. A second sample has n = 4 scores and M = 8. If the two samples are combined, then what is the mean for the combined sample?

a. 3

b. 4

c. 5

d. 6

c. 29/10 = 2.9

What is the mean for the population of scores shown in the frequency distribution table?

X: 5, 4, 3, 2, 1

f: 1, 2, 3, 3, 1

a. 15/10 = 1.5

b. 15/5 = 3.0

c. 29/10 = 2.9

d. 29/5 = 5.8

a. 25

After 5 points are added to every score in a distribution, the mean is calculated and found to be μ = 30. What was the value of the mean for the original distribution?

a. 25

b. 30

c. 35

d. Cannot be determined from the information given.