Unit 7 psych stat

PSY 3200

Unit #7 AS: Correlations

This assignment will examine your ability to analyze the relationship between two variables, create an equation for predicting one variable from the other, and to critique the results of the data. You will be given the data for 2 psychological experiments looking at the relationship between variables. For these sets of data you will: (1) use the SPSS program to calculate the correlation and create a scatterplot (2) provide the appropriate output given from the program (3) describe this relationship (both strength and direction, and in layman’s terms) (4) determine if these variables truly related or could there be a third variable at play (5) calculate the regression equation (showing your work) (6) use that regression equation to calculate a prediction; and (7) calculate the proportionate reduction in error. All work will be posted in a word document and uploaded to blackboard.

1) A psychologist is investigating the relationship between drinking coffee and sleep. She chooses 20 participants and measures how many cups of coffee they had the previous day and how many hours of sleep they got the night before. The data is presented below:

Coffee	Sleep
0	9.5
1	9.5
4	7
5	6
2	8
3	8.5
1	8
1	6
4	6
3	7
6	7
6	7.5
2	8.5
0	9
1	9
2	7
4	5
3	6
5	7
7	6

For this data you will:

· Use the SPSS program to calculate the correlation and create a scatterplot

· Provide the appropriate output

· How would you describe this relationship? (both strength and direction, and in layman’s terms)

· Are these variables truly related or could there be a third variable at play?

· Calculate the regression equation (show your work)

· How much sleep should someone get if they drink 5 cups of coffee in a day?

· Calculate the proportionate reduction in error

2) A psychologist is investigating the relationship of ambient temperature and water consumption. She chooses 20 participants and measures how much water they consumed throughout the course of a day and what the high temperature was for that day. The data is presented below:

Temperature (F)	Water consumption (oz)
75	16
83	20
85	25
85	27
92	32
97	48
99	48
88	34
87	35
77	22
78	14
98	22
89	41
98	45
78	19
92	41
84	38
71	23
88	29
78	27

For this data you will:

· Use the SPSS program to calculate the correlation and create a scatterplot

· Provide the appropriate output

· How would you describe this relationship? (both strength and direction, and in layman’s terms)

· Are these variables truly related or could there be a third variable at play?

· Calculate the regression equation (show your work)

· How much water should someone drink if the high temperature for that day was 70 degrees?

· Calculate the proportionate reduction in error