Psych 100A Quiz

Which of the following variables is measured on an ordinal scale (i.e., an ordinal variable)?

Select one:

a. Self-reported health (poor, fair, good, excellent)

b. Blood type

c. Type of living accommodation (House, Apartment, Trailer)

d. SAT scores

a

Which of the following variables is measured on an interval scale (i.e., an interval variable)?

Select one:

a. Gender

b. Hair color

c. Celsius temperature

d. Course grades (A, B, C, D)

c

Which of the following variables is measured on a ratio scale (i.e., a ratio variable)?

Select one:

a. Education level

b. Number of students

c. Likert scale responses

d. Nationality

b

A smartphone use study classifies respondents into four groups: female senior users, female young users, male senior users, and male young users. Which level of measurement describes this variable?

Select one:

a. Interval variable

b. Nominal variable

c. Ordinal variable

d. Ratio variable

b

A study examining coffee-drinking behaviors asked participants how ofen they drink coffee. Participants indicated their level of coffee-drinking behaviors using a 5-point Likert-type rating scale ranging from 1 ("Never Drink") to 5 ("Drink multiple cups per day"). Which level of measurement describes this variable?

Select one:

a.

Nominal variable

b.

Interval variable

c.

Quasi-Interval variable

d.

Ratio variable

c

A study was conducted at UCLA PSYCH 100A course to measure the effect of homework length on student performance on the final exam and overall satisfaction on the course. A total of 210 students were randomly assigned to either short homework (n = 105) or long homework (n = 105). At the start of the study, researchers collected a number of background variables (e.g., AGE, GPA, gender), and a 5-point satisfaction scale.

What level of measurement describes the treatment conditions variable (short homework or long homework).

Select one:

a. Nominal

b. Ratio variable

c. Interval variable

a

A study was conducted at UCLA PSYCH 100A course to measure the effect of homework length on student performance on the final exam and overall satisfaction on the course. A total of 210 students were randomly assigned to either short homework (n = 105) or long homework (n = 105). At the start of the study, researchers collected a number of background variables (e.g., AGE, GPA, gender), and a 5-point satisfaction scale.

What level of measurement describes the student GPA variable?

Select one:

a.

Numeric (also called continuous variable, including interval/ratio variable)

b.

Ordinal

c.

Nominal

a

A study was conducted at UCLA PSYCH 100A course to measure the effect of homework length on student performance on the final exam and overall satisfaction on the course. A total of 210 students were randomly assigned to either short homework (n = 105) or long homework (n = 105). At the start of the study, researchers collected a number of background variables (e.g., AGE, GPA, gender), and a 5-point satisfaction scale.

The satisfaction scale ranges from 1 (Strongly Dissatisfied) to 5 (Strongly Satisfied). What level of measurement describes the satisfaction scale?

Select one:

a.

Interval variable

b.

Quasi-Interval variable

c.

Ratio variable

d.

Nominal variable

b

Researchers are interested in studying factors related to teenage drinking frequency (higher scores = more frequent drinking). In particular, the researchers want to determine whether growing up with an alcoholic parent versus not has an influence on the frequency of drinking. Which of the following results would indicate that children of alcoholic parents drink more frequently?

Select one:

a. The centers of the two distributions differ, with children of alcoholics centered at a lower value

b. The centers of the two distributions differ, with children of alcoholics centered at a higher value

c. The spread of the two distributions differ, with children of alcoholics having more spread or variability

d. The centers of the two distributions are about the same

b

Researchers are interested in whether males or females have a more positive attitude towards smoking. A larger value indicates a more positive attitude. Which of the following results would indicate that one of the two gender groups gives systematically more positive ratings?

Select one:

a. The centers of the two distributions differ, with males centered at a lower value

b. The spread of the two distributions differ, with females having more spread or variability

c. The centers of the two distributions are about the same

a

A study of post-partum depression found a relatively even number of mothers with low, moderate, and high depression levels. What distribution shape best describes the depression variable?

Select one:

a. Normal

b. Positively skewed

c. Negatively skewed

d. Uniform

d

In a frequency distribution, which quantity describes the number of respondents providing a particular response?

Select one:

a. Count (Frequency)

b. Percent (% of total)

c. Cumulative percent (cumulative %)

a

In City A, the mean salary of individuals is $20,000, and the median salary is $2,000. Which of the following is most likely true about the distribution of salaries?

Select one:

a. Uniformly distributed

b. Normally distributed

c. Negatively skewed

d. Positively skewed

d

Consider the following set of depression scores: 1, 2, 2, 2, 6, 8, 9, 10.

What is the sample mean?

5

Consider the following set of depression scores: 1, 2, 2, 2, 6, 8, 9, 10.

What is the sample median?

4

Consider the following set of depression scores: 1, 2, 2, 2, 6, 8, 9, 10.

What is the sample mode?

2

A researcher wants to use a measure of central tendency to summarize the ethnicity breakdown of his sample. Which measures of central tendency can be computed for this variable? Note that the question is NOT asking which one you should use, but which one you COULD use.

mode

A researcher is studying the distribution of salaries and she wants to report the central tendency for the salaries. Which measures of central tendency can be computed for this variable? Note that the question is NOT asking which one you should use, but which one you COULD use as a REASONABLE measure.

mean, med, mode

A researcher calculates the standard deviation of salaries and obtains a value of zero. Which of the following is true?

Select one:

a. All salaries were identical

b. Salaries were normally distributed around the mean

c. A mistake was made, the standard deviation cannot equal zero

a

A researcher is summarizing a sample of ages and reports that the average difference between a respondent's age and the sample mean is 8 years. Which measure of variability is she reporting?

Select one:

a. Variance

b. Range

c. Standard deviation

c

Another researcher is summarizing a sample of ages and reports that the average squared difference between a respondent's age and the sample mean is 9 years. Which measure of variability is he reporting?

Select one:

a. Standard deviation

b. Variance

c. Range

b

A researcher summarized the descriptive statistics for exam anxiety scores. A higher score in her questionnaire reflects a higher level of anxiety. She found that for junior students, the sample mean was 20 and the standard deviation was 5, whereas for senior students, the sample mean was 15 and the standard deviation was 10. In which group are anxiety scores most similar to one another?

Select one:

a. Senior students

b. Junior students

b

A sample of exam anxiety scores has a mean of 20 and a standard deviation of 5. The sample standard deviation was computed using a formula with N-1 (the degrees of freedom) in the denominator. Which of the following is true regarding the N-1 value in the standard deviation formula?

Select one:

a. N-1 or N in the denominator has no impact on the accuracy of the sample standard deviation of depression scores

b. The sample standard deviation = 5, obtained from dividing by N-1, is a more accurate approximation of the population standard deviation of exam anxiety scores

c. We use N-1 to correct the equation because we must square deviation scores to eliminate negative signs

b

A sample of exam anxiety scores has a mean of 20 and a standard deviation of 5. Which of the following interpretations is definitely true?

Select one:

a. The average squared difference between a score and the mean is 5-points

b. The difference between the lowest and highest score is 25 points

c. All scores are within ± 10 points from the mean

d. All scores are within ± 5 points from the mean

e. 95% of scores are within ± 10 points from the mean

e

A researcher has a sample of exam anxiety scores with a mean of 20 and a standard deviation of 5. This researcher found out that he made a mistake when he recorded the scores. One participant should have a score of 40 instead of a score of 30. Which of the following statements is true after he corrects for that mistake?

Select one:

a. The standard deviation remains the same

b. The standard deviation becomes larger

c. The standard deviation becomes smaller

b

The population standard deviation formula has N in the denominator, whereas the sample standard deviation formula has N-1 in the denominator. What is the rationale for using N-1 rather than N?

Select one:

a. We don't know the number of observations in the full population, so we use N-1 as an estimate of the number of observations

b. Dividing by N would make the sample standard deviation a more accurate estimate of the population standard deviation

c. We don't know the population mean and hence use the sample mean as a replacement. As a consequence, the sum of squares tends to be too small. N-1 is used to counteract the effect from the small sum of squares.

c