Psychology Statistics Final Practice Exam Part 1

A population has SS = 100 and o^2 = 4. What is the value of Σ(X-u) for the population?

0

What is the value of the median for the following set of scores? Scores: 1, 3, 4, 6, 8, 12, 13, 23, 25, 26

10

What is the value of Σ(X-2)^2 for the scores 2, 3, 5?

10

For the following distribution, what percentage of the individuals have scores of X=1? X: 5, 4, 3, 2, 1 F: 2, 8, 5, 3, 2 a. 2% b. 5% c. 10% d. 20%

10%

Consider the following data set of eight scores: 2, 4, 8, 8, 11, 12, 13, 14. Let's say we grouped the data into these intervals: 0-4, 5-9, 10-14. What is the mode of these scores?

10-14

In a population of N = 10 scores, the smallest score is X = 8 and the largest score is X = 20. What is the range for this population?

13

Which set of scores have the smallest standard deviation?

145, 143, 145, 147

A population of N = 100 scores has u = 30 and o = 4. What is the population variance?

16

What is the value of Σ(X+1) for the scores 2, 4, 7?

16

What is the mode for the population of scores shown in the frequency distribution table? X: 5, 4, 3, 2, 1 F: 1, 2, 3, 4, 2

2

What is the value of SS (sum of squared deviations) for the following sample? Sample: 1, 3, 2, 2 a. 0.50 b. 2 c. 4 d. 18

2

For the data in the following table, what is the value of ΣX? X: 4, 3, 2, 1 F: 1, 2, 4, 2 a. 10 b. 15 c. 20 d. Cannot be determined from the table

20

Consider the following sample: 65, 70, 72, 80, 88. What is the range?

24

A sample of n = 25 scores has M = 20 and s^2 = 9. What is the sample standard deviation?

3

A sample of n=8 has a mean of M=10. After one score is removed from the sample, the mean for the remaining score is found to be M=11. What was the score that was removed?

3

For the following frequency distribution of exam scores, how many students had scores lower than X=80? X: 90-94, 85-89, 80-84, 75-79, 70-74 F: 3, 4, 5, 2, 1 a. 2 b. 3 c. 7 d. Cannot be determined

3

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, 4, 2 a. 15/5= 3 b. 15/12= 1.25 c. 32/5= 6.60 d. 32/12= 2.67

32/12= 2.67

A population of N= 10 scores has a standard deviation of o = 2. What is the value of SS, the sum of the squared deviations, for this population?

40

The sum of the squared deviation scores is SS = 20 for a sample of n = 5 scores. What is the variance for this sample?

5

Consider the following sample: 65, 70, 72, 80, 88. If we multiplied each of the scores by 9, what would be the new variance?

6642

One sample has n=4 scores and M=10. A second sample has n=8 scores and M=4. If the two samples are combined, what is the mean for the combined sample?

72/12 = 6

What is the value of ΣX+1 for the scores 1, 0, 2, 4?

8

What is Σ(X-4) for the following distribution? X: 8, 6, 4, 2, 0 F: 4, 8, 8, 6, 3

8

Consider the following sample: 65, 70, 72, 80, 88. What is the variance?

82

A sample of n=15 scores ranges from a high of X=11 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?

9

Consider the following data set of eight scores: 2, 4, 8, 8, 11, 12, 13, 14. What is the mean of the scores?

9

Consider the following data set of eight scores: 2, 4, 8, 8, 11, 12, 13, 14. What is the median of the scores?

9.5

A biologist records the number of trout, bass, perch, and other types of fish caught in a local lake during a 2-week period. If the results are organized in a frequency distribution graph, what kind of graph should be used?

A bar graph

What is the first step to be performed when computing Σ(X+2)^2?

Add 2 points to each score

A sample has a mean of M=86. If one new person is added to the sample, what effect will it have on the sample mean?

Cannot be determined

For the following frequency distribution of exam scores, what is the lowest score on the exam? X: 90-94, 85-89, 80-84, 75-79, 70-74 F: 3, 4, 5, 2, 1 a. X=70 b. X=74 c. X=90 d. Cannot be determined

Cannot be determined

For the following frequency distribution, what is ΣX? X: 30-34, 25-29, 20-24, 15-19, 10-14 F: 1, 1, 3, 2, 1 a. 8 b. 90 c. 110 d. Cannot be determined

Cannot be determined

In a population of N= 6, five of the individuals all have scores that are exactly 1 point above the mean. From this information, what can you determine about the score for the 6th individual?

It is below the mean by 5 points

A researcher measures eye color for a sample of n = 50 people. Which measure of central tendency would be appropriate to summarize the measurements?

Mode

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

The students in a psychology class seemed to think that the midterm exam was very easy. If they are correct, what is the most likely shape for the distribution of exam scores?

Negatively skewed

A researcher uses an anonymous survey to investigate the television-viewing habits of American adolescents. The goal of the research is to determine the average number of hours each day that American adolescents spend watching television. The researcher is trying to determine a number that is an example of a _____________

Parameter

A researcher uses an anonymous survey to investigate the television-viewing habits of American adolescents. Based on the set of 356 surveys that were completed and returned, the researcher finds that these students spend an average of 3.1 hours each day watching television. For this study, the set of 365 students who returned surveys is an example of a ____________

Sample

What is the final step to be performed when computing Σ(X-2)^2?

Sum the squared values

A researcher conducts an experiment to determine whether moderate doses of St. Johns Wort have any effect of memory for college students. For this study, what is the independent variable?

The amount of St. Johns Wort given to each participant

What does it mean for a statistic to be resistant? Name one statistic that is resistant.

When an extreme score either changes the value of a statistic a little or not at all. The median is resistant.

For the following frequency distribution of quiz scores, how many individuals took the quiz? X: 5, 4, 3, 2, 1 F: 6, 5, 5, 3, 2 a. n=6 b. n=15 c. n=21 d. Cannot be determined from the table

n=21

A population has u = 50 and o = 5. If 10 points are added to every score in the population, what are the new values for the mean and standard deviation?

u = 60 and o = 5