Gravetter - Statistics for the Behavioral Sciences (Homework)

James Finch

Statistics, Fall 2010

Instructor: Dr. Friendly

Current Score: 18/25

Due: Saturday, November 6, 2010 23:00 EDT

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Question

Points

1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16
2	7/8	0/1	2	1	0/1	0/1	0/1	0/1	0/1	1	1	1	1	1	1

Total

18/25

Description

Here are some textbook questions from Statistics for the Behavioral Sciences 8/e by Frederick J. Gravetter and Larry B. Wallnau published by Wadsworth.

Questions 1-5 are end of chapter questions.

Question 6 is a simulation question.

Questions 7-10 are tutorial questions.

Questions 11-16 are test bank questions.

Click here for a list of all of the questions coded in WebAssign.

Instructions

This demo assignment allows many submissions and allows you to try another version of the same question for practice.

1. 2/2 points All Submissions Notes Question: GravStat8 1.EOC.012.

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2/2

Oxytocin is a naturally occurring brain chemical that is nicknamed the "love hormone" because it seems to play a role in the foundation of social relationships such as mating pairs and parent-child bonding. A recent study demonstrated that oxytocin appears to increase people's tendency to trust others (Kosfeld, M., Heinrichs, M., Zak, P. J., Fischbacher, U., & Fehr, R., 2005). Using an investment game, the study demonstrated that people who inhaled oxytocin were more likely to give their money to a trustee compared to people who inhaled an inactive placebo. For this experimental study, identify the independent variable and the dependent variable.

(a) The independent variable is which of the following?

the substance that is inhaled, either oxytocin or the inactive placebo whether oxytocin occurs in the brain or not the number of social relationships a person has whether or not the people were willing to give their money to the trustee

Your answer is correct.

(b) The dependent variable is which of the following?

Your answer is correct.

2. 7/8 points All Submissions Notes Question: GravStat8 2.EOC.014.

Question part

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1	2	3	4	5	6	7	8
1	1	1	1	1	1	1	0/1
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7/8

For the following set of scores:

Scores:	3,	3,	1,	5,	5,	3,	4,	2,	2,	7
	1,	4,	4,	3,	3,	4,	1,	1,	6,	2

(a) Construct a frequency distribution table.

X	f
7	Enter an exact number. 1
6	Enter an exact number. 2
5	Enter an exact number. 3
4	Enter an exact number. 4
3	Enter an exact number. 5
2	Enter an exact number. 6
1	Enter an exact number. 7

(b) Draw the polygon showing the distribution. (Be sure to draw a line segment down to the X axis (zero frequency) at each end of the range of scores.)

Flash Player version 10 or higher is required for this question.
You can get Flash Player free from Adobe's website.

3. 0/1 points All Submissions Notes Question: GravStat8 3.EOC.008.

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In 2007, the American golfer Tiger Woods competed in 16 PGA golf tournaments. He finished 1^st seven times, 2^nd three times, and one time each in 6^th, 9^th, 12^th, 15^th, 22^nd, and 37^th. Find the standard deviation of his finishing position for the year. (Assume that finishing position is a discrete variable, answer as a whole number.)
Your answer is incorrect.

4. 2/2 points All Submissions Notes Question: GravStat8 4.EOC.012.

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2/2

On an exam μ = 70, you obtain a score of X = 90.

(a) Would you prefer that the exam distribution had σ = 2 or σ = 10? (Sketch the distribution, and locate the position of X = 90 in each. Do this on paper. Your instructor may ask you to turn in this work.)
σ = Your answer is correct.

(b) If your score is 65, would you prefer σ = 2 or σ = 10? (Again, sketch each distribution to determine how the value of σ affects your position relative to the rest of the class. Do this on paper. Your instructor may ask you to turn in this work.)
σ = Your answer is correct.

5. 1/1 points All Submissions Notes Question: GravStat8 8.EOC.017.

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1/1

Montarello and Martins (2005) found that fifth-grade students completed more mathematics problems correctly when simple problems were mixed in with their regular math assignments. To further explore this phenomenon, suppose that a researcher selects a standardized mathematics achievement test that produces a normal distribution of scores with a mean of μ = 100 and a standard deviation of σ = 18. The researcher modifies the test by inserting a set of easy problems among the standardized questions, and gives the modified test to a sample of n = 36 students. If the average test score for the sample is M = 104, is this result sufficient to conclude that inserting the easy questions improves student performance? Use a one-tailed test with α = .01.

H₀: μ ≤ 100 (performance is not increased). The critical region consists of z-scores beyond z = +2.33. For these data, σ_M = 3 and z = 1.33. Fail to reject H₀ and conclude that performance is not significantly higher with the easy questions added. H₀: μ ≥ 100 (performance is increased). The critical region consists of z-scores beyond z = +2.33. For these data, σ_M = 3 and z = 1.33. Reject H₀ and conclude that performance is significantly higher with the easy questions added.

Your answer is correct.

6. –/1 points Notes Question: GravStat8 3.Sim.01.

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0/1

7. –/1 points Notes Question: GravStat8 1.Tut.04.

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0/1

To receive credit, you must enter the correct answer in the blue box, click Submit for Credit, then click OK in the pop-up box. Use the Tutor Steps for help in finding the right answer.

8. –/1 points Notes Question: GravStat8 1.Tut.05.

Question part

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1
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0/1

To receive credit, you must enter the correct answer in the blue box, click Submit for Credit, then click OK in the pop-up box. Use the Tutor Steps for help in finding the right answer.

9. –/1 points Notes Question: GravStat8 3.Tut.01.

Question part

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1
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0/1

To receive credit, you must enter the correct answer in the blue box, click Submit for Credit, then click OK in the pop-up box. Use the Tutor Steps for help in finding the right answer.

10. –/1 points Notes Question: GravStat8 5.Tut.01.

Question part

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1
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0/1

To receive credit, you must enter the correct answer in the blue box, click Submit for Credit, then click OK in the pop-up box. Use the Tutor Steps for help in finding the right answer.

11. 1/1 points All Submissions Notes Question: GravStat8 3.TB.001.

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1/1

What is the mean for the following sample of scores?

Scores: 1, 2, 5, 4

12 6 4 3

Your answer is correct.

12. 1/1 points All Submissions Notes Question: GravStat8 3.TB.006.

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1/1

A sample of n = 5 scores has a mean of M = 12. What is

x for this sample?

5(12) = 60 5/12 = 0.417 cannot be determined from the information given 12/5 = 2.40

Your answer is correct.

13. 1/1 points All Submissions Notes Question: GravStat8 3.TB.007.

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1/1

A population has a mean of μ = 4 and

x = 48. How many scores are in this population?

48 192 cannot be determined from the information given 12

Your answer is correct.

14. 1/1 points All Submissions Notes Question: GravStat8 3.TB.022.

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1/1

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

not enough information to describe the sixth score below the mean by 1 point also above the mean by 1 point below the mean by 5 points

Your answer is correct.

15. 1/1 points All Submissions Notes Question: GravStat8 3.TB.003.

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1/1

A population of N = 6 scores has

x = 48. What is the population mean?

12 8 288 48

Your answer is correct.

16. 1/1 points All Submissions Notes Question: GravStat8 3.TB.013.

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1/1

A set of N = 20 exam scores has a mean of μ = 50. The instructor discovered that an error was made grading one exam, so 20 points are added to that student's score. After adding the 20 points, what is the new mean for the class?

51 cannot be determined from the information given 50 70

Your answer is correct.

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Gravetter - Statistics for the Behavioral Sciences (Homework)

Current Score: 18/25