Hi Dr. Mash,I am student # 175861. You just completed a big statistics project for me intitled Psy380-RS-Project 3. I have a much easier homework that is due this Sunday in Webassign. I'm not sure if

PSY-280 NTRODUCTION TO PROBABILITY AND STATISTICS

A researcher measures the relationship between sleep medication use (times used per week) and time spent working (in hours per week). Answer the following questions based on the results provided.

Sleep Medication Use	Time Spent Working
10	16
5	40
9	20
4	32

Part (a)

Compute the Pearson correlation coefficient. (Round your answer to three decimal places.)

Part (b)

Multiply each measurement of drug use times 3 and recalculate the correlation coefficient. (Round your answer to three decimal places.)

Part (c)

Divide each measurement in half for time spent working and recalculate the correlation coefficient. (Round your answer to three decimal places.)

A therapist specializing in family counseling measures the relationship between partners and marital satisfaction. Husbands and wives rated how satisfied they were in their marriage using a 7-point rating scale ranging from 1 (not satisfied at all) to 7 (very satisfied). Using the hypothetical data given in the following table, compute the Pearson correlation coefficient. (Round your answer to three decimal places.)

Husband	Wife
X	Y
1	5
2	5
3	5
4	5
5	5
6	5
7	5

A researcher measures the relationship between Internet use (hours per week) and social interaction (hours per week) in a sample of 10 students. The following table lists the hypothetical results of this study.

Internet Use	Social Interaction
X	Y
7	4
9	5
6	6
6	7
11	5
3	7
3	2
6	4
3	9
12	2

(a) Compute the Pearson correlation coefficient. (Round your answer to three decimal places.)

(b) Compute the coefficient of determination. (Round your answer to three decimal places.)

(c) Using a two-tailed test at a 0.05 level of significance, state the decision to retain or reject the null hypothesis.

Retain the null hypothesis. Reject the null hypothesis.

Employers often use standardized measures to gauge how likely it is that a new employee with little to no experience will succeed in their company. One such factor is intelligence, measured using the Intelligence Quotient (IQ). To show that this factor is related to job success, an organizational psychologist measures the IQ score and job performance (in units sold per day) in a sample of 10 new employees.

IQ	Job Performance
100	20
115	34
108	21
98	19
120	40
147	51
132	49
85	60
105	29
110	36

(a) Convert the following data to ranks and then compute a Spearman correlation coefficient. (Round your answer to three decimal places.)

(b) Using a two-tailed test at a 0.05 level of significance, state the decision to retain or reject the null hypothesis.

Retain the null hypothesis. Reject the null hypothesis.

To test whether extracurricular activity is a good predictor of college success, a college administrator records whether students participated in extracurricular activities during high school and their subsequent college freshman GPA.

Extracurricular Activity	College Freshman GPA
Yes	3.54
Yes	3.32
Yes	3.95
Yes	3.75
No	2.91
No	3.88
No	3.42
No	2.77
No	3.93
No	2.82

(a) Code the dichotomous variable and then compute a point-biserial correlation coefficient. (Round your answer to three decimal places.)

(b) Using a two-tailed test at a 0.05 level of significance, state the decision to retain or reject the null hypothesis. Hint: You must first convert r to a t-statistic.

Retain the null hypothesis. Reject the null hypothesis.

A therapist measures the relationship between a patient's expectations that therapy will be successful and the actual success of the therapy. The following table shows the results of this hypothetical study using a sample of 50 clients.

		Therapy Successful
Yes	No	Totals
Client expects success	Yes	20	8	28
No	6	16	22
Totals	26	24

(a) Compute the phi correlation coefficient. (Round your answer to three decimal places.)

(b) Using a two-tailed test at a 0.05 level of significance, state the decision to retain or reject the null hypothesis. Hint: You must first convert r to χ2.

Retain the null hypothesis. Reject the null hypothesis.

Nobre and Pinto-Gouveia (2008) measured the relationship between emotion and thoughts of low self-body image. The following table shows a portion of their results for the correlations between thoughts of low-self body image and four types of emotions.

Correlations Between Four Emotions and Low Self-Body Image (n = 163)
Emotions	Thoughts of Low Self-Body Image
Sadness	0.24**
Guilt	0.27**
Pleasure	−0.25**
Satisfaction	−0.37**
**p < 0.01.

(a) List the emotions that showed a significant positive correlation with thoughts of low self-body image. (Select all that apply.)

guilt pleasure sadness satisfaction

(b) List the emotions that showed a significant negative correlation with thoughts of low self-body image. (Select all that apply.)

sadness guilt satisfaction pleasure

A social psychologist tests whether the size of a toy in cereal boxes can predict preferences for that cereal.
Identify the predictor variable.

liking for the cereal size of cereal boxes liking for the toy size of a toy in a cereal box

Identify the criterion variable.

size of a toy in a cereal box liking for the toy liking for the cereal size of cereal boxes

Part (c)

A military officer tests whether the duration of an overseas tour can predict the morale among troops overseas.
Identify the predictor variable.

duration of overseas tour troop morale number of troops duration of good morale

Identify the criterion variable.

troop morale duration of overseas tour duration of good morale number of troops

For each of the following regression equations, explain how the criterion variable (Y) changes as the predictor variable (X) increases. Hint: You can find the answer by looking at the equation.

(a)

= 0.53X − 9.40

The criterion variable increases. The criterion variable decreases. The criterion variable remains the same.

(b)

= −5.02X − 0.60

The criterion variable increases. The criterion variable decreases. The criterion variable remains the same.

(c)

= 2.60X + 10

The criterion variable increases. The criterion variable decreases. The criterion variable remains the same.

(d)

= −7.87X + 12

The criterion variable increases. The criterion variable decreases. The criterion variable remains the same.

An animal trainer tests whether the number of hours of obedience training can predict where a dog places in a dog show. The hypothetical data are given below.

Hours of Training	Place in Breed Show
X	Y
19	1
6	6
12	2
8	4

In terms of the method of least squares, which of the following regression lines is the best fit for these data?

= 1.8X + 4.25

= −1.8X − 4.25

= 0.357X − 7.266

= −0.357X + 7.266

A forensic psychologist tests the extent to which the age of a criminal (X) predicts the age of the victim (Y) for nonviolent crimes. The psychologist uses the case files to record the age of five criminals and the age of the victim in those cases. The hypothetical data are listed in the following table.

Age of Criminal	Age of Victim
X	Y
33	25
25	21
28	26
18	23
13	17

(a) Compute the method of least squares to find the equation of the regression line. (Round your answers to three decimal places.)
= X +
(b) Use the regression equation to determine the predicted age of a victim of a nonviolent crime when the criminal is 21 years old. (Round your answer to three decimal places.)
years old

An instructor measured quiz scores and the number of hours studying among a sample of 20 college students. If

SSXY = 44,

SSX = 95,

MY = 7,

and

MX = 5,

then what is the regression equation for this sample? (Round your numerical values to three decimal places.)
= X +

A researcher tested whether time of day could predict mood in a sample of 19 college students. If

SSresidual = 272,

then what is the standard error of estimate in this sample?

A psychologist noted that people have more difficulty sleeping in a bright room than in a dark room. She measured whether the intensity of the light could predict the time it took a sample of 4 participants to fall asleep. The data for this hypothetical study are listed in the following table.

Intensity of Light (in watts)	Time It Took to Sleep (in minutes)
X	Y
5	9
10	17
20	30
40	36

Compute an analysis of regression for this hypothetical study. (Round your answers to two decimal places.)

Source of Variation	SS	df	MS	Fobt
Regression
Residual (error)
Total

Make a decision to retain or reject the null hypothesis. (Assume alpha equal to 0.05.)

Retain the null hypothesis. Reject the null hypothesis.

A sports psychologist tested whether the number of team wins in the previous season can predict the number of wins in the following season in a sample of 32 teams. Complete the regression table for this hypothetical study. (Round your value for Fobt to two decimal places.)

Source of Variation	SS	df	MS	Fobt
Regression	43
Residual (error)			7
Total

Make a decision to retain or reject the null hypothesis. (Assume alpha equal to 0.05.)

Retain the null hypothesis. Reject the null hypothesis.