Deck 16: Data Preparation and Univariate Statistics

Question 1

A professor tells his students the results of the first exam: six students received an A, twelve students received a B, fifteen students received a C, and three students received an F. In statistical terms, this information is a

A) measure of variability.
B) measure of central tendency.
C) measure of standard deviation.
D) frequency distribution.

Answer 1

D

Question 2

Which measure of central tendency would probably be the most appropriate for analyzing the ratings (on a 1 to 7 scale) of a professor's teaching skills?

A) Mean
B) Mode
C) Median
D) Meridian

Answer 2

A

Question 3

Which of the following is NOT a method of checking and cleaning the data?

A) Comparing the entered data with the original questionnaires
B) Calculating descriptive statistics
C) Computing a frequency distribution
D) Creating new data for participants with missing data

Answer 3

D

Question 4

After all of the data have been entered into the computer, the first thing that the researcher should do is to

A) transform the data.
B) check and clean the data.
C) conduct the statistical analyses.
D) delete responses that do not support the theory.

Question 5

Which of the following is NOT a descriptive statistic?

A) The mean
B) The standard deviation
C) The p-value
D) The standard score

Question 6

A researcher might delete a variable before analyzing the data when

A) the variable shows the expected relationship with the independent variable, but another variable does not.
B) the statistical analysis reveals that the variable did not have a significant impact on the independent variable.
C) a reliability analysis indicates that the variable does not measure the same thing that other variables, designed to measure the same conceptual variable, do.
D) the relationship of the variable to the independent variable is not in the predicted direction.

Question 7

For which of the following reasons would data be deleted before the data are analyzed?

A) If the data contain outliers
B) If there are too many participants for analysis
C) If the participants' answers seem too low
D) When some of the responses do not support the research hypothesis

Question 8

Imagine the distribution of salaries in a large corporation. Which of the following statistics is likely to be the largest?

A) The median
B) The mean
C) The mode
D) The minimum

Question 9

The process of deleting responses on both ends of the distribution of a variable is known as

A) outlier deletion.
B) transforming the data.
C) trimming the data.
D) cleaning the data.

Question 10

Which of the following is NOT part of preparing data for statistical analysis?

A) Entering data into the computer
B) Computing descriptive statistics
C) Checking for missing data
D) Checking the distribution of the population parameters

Question 11

A grouped frequency distribution is graphically represented using a

A) bar chart.
B) histogram.
C) polygon.
D) bell-shaped curve.

Question 12

What is the measure of central tendency which represents the most frequently occurring value in a variable?

A) Mean
B) Median
C) Mode
D) Media

Question 13

The frequency of nominal data can be graphically presented using a

A) bar chart.
B) histogram.
C) polygon.
D) bell-shaped curve.

Question 14

A researcher might delete a participant's responses when

A) the responses from the individual are very extreme or unusual.
B) no other responses are missing for that participant.
C) the participant's responses do not correspond with the hypothesis.
D) the participant gave an above average response to each question.

Question 15

The range is equal to the

A) mean minus the mode.
B) maximum score minus the mean.
C) mean minus the median.
D) maximum score minus the minimum score.

Question 16

The difference between a person's score on the variable (x) minus the mean of the variable is known as the

A) confidence interval.
B) mean deviation.
C) degrees of freedom.
D) margin of error.

Question 17

Which of the following represents the mode of the following eight numbers: 1 2 2 4 5 5 5 8

A) 2
B) 3
C) 4
D) 5

Question 18

A researcher measures all of the students in her class, and determines that the mean of their IQ scores is 105. This information is a(n)

A) inferential statistic.
B) descriptive statistic.
C) analyzing statistic.
D) control variable.

Question 19

Which of the following is NOT a reason for deleting the data of a participant?

A) The participant's responses were not in the predicted direction.
B) The participant did not pass the suspicion check.
C) The participant had a large number of unusual responses.
D) The participant was not able to perform the necessary task.

Question 20

The statement that "Japanese children are more intelligent than American children" is an example of the use of

A) inferential statistics.
B) descriptive statistics.
C) standard deviations.
D) frequency distributions.

Question 21

Assume that a random sample of twenty-three students at your university were found to have a mean GPA of 2.8 with a standard deviation of .8. What would be the best guess of the average GPA of the entire university?

A) 2.8
B) 3.6
C) 2.0
D) 3.0

Question 22

Which of the following statistics is used to indicate how accurately a sample mean predicts a population mean?

A) The sum of squares
B) The F value
C) The z score
D) The confidence interval

Question 23

If A = 5, B = 4 and C = 2, then Σ (A, B, C) =

A) 5
B) -1
C) 40
D) 11

Question 24

A quick way to check the data once it has been entered is to

A) compare all of the data with the original questionnaires.
B) wait until a statistical analysis is completed before checking the data.
C) conduct a frequency distribution.
D) conduct a chi-square analysis.

Question 25

Descriptive statistics are more precise when the sample is larger. This is predicted by the

A) standard error.
B) central tendency measures.
C) normal distribution.
D) central limit theorem.

Question 26

According to the _________, descriptive statistics calculated on large samples provide more precise estimates of population parameters than do these same statistics calculated on small samples.

A) central limit theorem
B) confidence intervals
C) unbiased estimator of the population mean
D) sample standard deviation

Question 27

The mean of the standard scores of a variable is always equal to _________ and the standard deviation is always equal to ________.

A) 0; 1
B) 1; 1
C) 1; 0
D) 0; 0

Question 28

Which of the following measures dispersion?

A) Mean
B) Percentile rank
C) Sum of squares
D) Mode

Question 29

Computers are useful for collecting and analyzing statistical data because

A) they are less expensive than analyzing data by hand.
B) they allow p-values to be calculated.
C) they can decrease calculation errors.
D) new methods of statistical analysis are not necessary.

Question 30

Descriptive statistics represent the data from a ________ whereas parameters represent the data from a __________.

A) sample; population
B) population; sample
C) normal distribution; control group
D) binomial distribution; population

Question 31

Nominal variables, such as gender and ethnicity, are usually entered into a data analysis program as

A) letters corresponding to each level of the variable.
B) a ratio scale.
C) numbers corresponding to each level of the variable.
D) words such as male, female, black, and white.

Question 32

Which of the following is used to specify how precisely the population mean has been estimated?

A) The unbiased estimator
B) The sample mean
C) The size of the population
D) The confidence interval

Question 33

Which of the following statements is true about a random sample?

A) The mean of the sample will be the best guess of the mean of the population, no matter how large the sample is.
B) The mean of the sample will be the best guess of the mean of the population but only in very large samples.
C) The mean of the sample will provide the best guess of the mean of the population, but only if the sample is normally distributed.
D) The mean of the sample will provide the best guess of the mean of the population, but only if there are outliers in the sample.

Question 34

If the lower limit of a confidence interval is 1.5 and the upper limit of a confidence interval is 5.5, we can state that

A) a score of 6 is impossible.
B) 95 percent of the scores should fall between 1.5 and 5.5.
C) the confidence level is extremely small.
D) the distribution is normal.

Question 35

A z score represents

A) the mean score in a sampling distribution.
B) the distance of a score from the median.
C) the distance of a score from the mean of the variable in standard deviation units.
D) the distance of the mean minus the standard deviation.

Question 36

Which of the following measures central tendency?

A) Mode
B) Standard deviation
C) Sum of squares
D) Variance

Question 37

The exact width of the confidence interval is determined by using which of the following statistics?

A) Z score
B) Median
C) P-value
D) Student's t

Question 38

Joe has a score of 8 on a variable that has a mean of 10 and a standard deviation of 2. What is Joe's standard score on the variable?

A) 12
B) -1
C) 8
D) -2