Deck 12: Descriptive Statistics

Question 1

The median is strongly influenced by extreme scores.

Answer 1

False

Question 2

A histogram is used to display the distribution of a single variable.

Answer 2

True

Question 3

Research has shown that men have stronger leadership abilities than women.

Answer 3

False

Question 4

The median is the most common score in a distribution.

Question 5

Cohen's d is a measure of the size of the difference between two group or condition means.

Question 6

The standard deviation is one half the range.

Question 7

Pearson's r is the mean cross-product of two sets of z scores.

Question 8

In a positively skewed distribution, the mean is greater than the median.

Question 9

A bimodal distribution has two distinct peaks.

Question 10

In a positively skewed distribution, most scores are above the mean.

Question 11

A distribution with two distinct peaks is called binomial.

Question 12

A distribution can have more than one mode.

Question 13

A frequency table is used to display the distribution of a variable.

Question 14

The variance is the square root of the standard deviation.

Question 15

A Pearson's r of -.45 represents a stronger relationship than a Pearson's r of +.37.

Question 16

A histogram is used to display the relationship between two variables.

Question 17

In a negatively skewed distribution, most scores are above the mean.

Question 18

In psychological research, a Pearson's r of .50 represents a weak relationship.

Question 19

A Cohen's d of 1.00 means that two group means differ by one standard deviation.

Question 20

Pearson's r is an appropriate measure for both linear and nonlinear relationships.

Question 21

Raw data are data that have not yet been analyzed.

Question 22

What is plotted on the Y-axis of a histogram?

A) the mean score
B) the variable of interest
C) the participants' names
D) the frequency of each score

Question 23

There is a statistical relationship between two variables if which of the following is true?

A) The variables are measured on the same scale.
B) One of the variables has a higher mean than the other.
C) The average level of one variable differs across levels of the other.
D) The variables are conceptually similar (e.g., intelligence and common sense).

Question 24

It is impossible to say what the results of a study are until the inferential statistics have been done.

Question 25

In psychological research, which of the following is considered a strong relationship?

A) d = 0.50
B) r = - .30
C) r = .50
D) d = 0.20

Question 26

In a computer data file, each participant is usually represented by a column of data.

Question 27

If Esther has a z score of -0.10 on a test of reading ability, which of the following is true?

A) Esther has an extremely low reading ability.
B) Esther's reading ability is close to the average.
C) The test is biased against girls.
D) A mistake was made in computing her z score.

Question 28

In a positively skewed distribution, which of the following is true?

A) The mean is greater than the median.
B) The mean is less than the median.
C) The mean is the same as the median.
D) It is impossible to tell.

Question 29

Conceptually, what is the standard deviation?

A) The average amount that the scores in a distribution differ from the mean.
B) The difference between the highest and lowest scores in a distribution.
C) The mean of the squared scores.
D) Half the difference between the highest and lowest scores in a distribution.

Question 30

Researchers should avoid using their data to answer questions that they had not planned on answering when they conceptualized the study.

Question 31

The mean score on a test of agreeableness is 27 with a standard deviation of 8. Rudolfo got a score of 25 on this test. What is his z score?

A) -0.25
B) -0.40
C) -2.00
D) There is not enough information to tell.

Question 32

Nora likes to eat her lunch at a different fast food restaurant every day, so the amount she spends for lunch per day is a variable. Which of the following would be a reasonable estimate of the standard deviation of this variable?

A) 3 cents
B) 1 dollar
C) 10 dollars
D) 30 dollars

Question 33

Jane computes the variance for a set of data and gets the correct answer of 16. What is the standard deviation for this same set of data?

A) 16
B) 8
C) 2
D) 4

Question 34

On a research methods exam, most of the students did well but a few did poorly. Which of the following is most clearly true?

A) The scores are positively skewed.
B) The scores are negatively skewed.
C) The distribution is bimodal.
D) The distribution has only one tail.

Question 35

Complex sets of data are likely to include "patterns" that occurred entirely by chance.

Question 36

Which of the following represents the strongest statistical relationship?

A) d = 0.80
B) r = - .40
C) r = + .40
D) d = 0.10

Question 37

Which of the following measures of central tendency can be used for a categorical variable?

A) mean
B) median
C) mode
D) none of the above

Question 38

Which of the following is most clearly a statement about a statistical relationship between variables?

A) About one-third of Americans have a psychological disorder at some time in their lives.
B) Summer temperatures in Phoenix often exceed 100 degrees Fahrenheit.
C) "Pain-Away" is more effective at treating headaches than its nearest competitor.
D) Prejudice is a serious problem.

Question 39

A researcher shows that doctors who act more confidently are liked better by their patients … but only up to a point. If they act too confidently, their patients start to like them less. Which of the following best describes this result?

A) There is no relationship between physician confidence and patient liking.
B) The relationship between physician confidence and patient liking is nonlinear.
C) There is a strong negative relationship between physician confidence and patient liking.
D) It is a bimodal distribution

Question 40

What is the median for the set of data below?

A) 5
B) 8
C) 8.5
D) 49.5

Question 41

Why should researchers be cautious about unexpected results in their data-even when those results are statistically significant?

Question 42

Which of the following best describes the statistical relationship between people's heights and weights?

A) perfect
B) negative
C) extremely weak
D) positive

Question 43

Imagine you find an unexpected but statistically significant result in your data. Which of the following courses of action makes the most sense?

A) ignore it
B) immediately write it up for publication
C) follow up on it in a new research study
D) none of the above

Question 44

Which of the following describes Pearson's r?

A) It is the average amount by which the scores in two sets of data differ from each other.
B) It is the cross-product of two variances.
C) It is average difference between X and Y, divided by N.
D) It is the mean cross-product of two sets of z scores.

Question 45

Give an example of an outlier in a set of data. What are at least two ways that you could deal with this outlier?

Question 46

What is standard term for data that have been collected but not yet organized and analyzed?

A) unorganized data
B) preliminary data
C) raw data
D) convenience data

Question 47

Pearson's r is NOT appropriate for which of the following?

A) negative relationships
B) nonlinear relationships
C) weak relationships
D) extremely strong relationships

Question 48

Identify two psychological variables that you think are probably statistically related. If you were to collect data on this relationship, which measure of relationship strength (d or r) would you use to describe it? What value of d or r would you expect and why?

Question 49

In a typical computer data file, which of the following is generally true?

A) Each column is labeled.
B) Each variable is represented by one or more columns.
C) Each participant is represented by one row.
D) all of the above

Question 50

Explain what Pearson's r is for someone who is not already familiar with statistics.

Question 51

Restriction of range is likely to be a problem in which of the following studies?

A) a study on the relationship between extroversion and risk seeking among college students
B) a study on the relationship between age and attitude toward homosexuality among college students
C) a study on the relationship between extroversion and leadership ability among the employees of a large corporation
D) a study on the relationship between income and happiness among New York City residents

Question 52

Which of the following pairs of variables seems most likely to have a negative relationship?

A) intelligence and grade point average
B) people's heights and weights
C) shyness and number of friends
D) the amount people exercise and how much they enjoy sports

Question 53

A research methods student conducts a study on the relationship between people's level of extroversion and the number of close friends they have. She computes Pearson's r, which comes out to be - 1.70. Which of the following is most clearly true?

A) The relationship between the two variables is weak.
B) More extroverted people have fewer friends.
C) She ought to use a bar graph to display her results.
D) She made an error in computing Pearson's r.

Question 54

Which of the following would fall into the category of "preliminary analyses?"

A) computing Cronbach's alpha for your dependent variables
B) checking for outliers
C) examining the distributions of your dependent variables
D) all of the above

Question 55

Which of the following is true of outliers?

A) They must be removed from the data.
B) They must be included in the final analyses.
C) They invalidate the results of a study.
D) Their removal should have a reasonable justification.

Question 56

A research methods instructor gives an exam. Assuming this instructor wants the students to do well, would he or she prefer to see a positively skewed distribution of scores or a negatively skewed distribution of scores? Explain why.

Question 57

Explain why the median is sometimes a better measure of central tendency than the mean.