Statistics - SPSS Projects

Two brands of refrigerators, A and B, are guaranteed for one year. In a random sample of 100 refrigerators

Problem 5: Two brands of refrigerators, A and B, are guaranteed for one year. In a random sample of 100 refrigerators of brand A, 24 were observed to fail before the guarantee period ended. A random sample of 120 brand B refrigerators also revealed 24 failures during the guarantee period.

Estimate the true difference between population proportions of failures during the guaranteed period with a confidence of 95%.
Is there a discernible difference between these two brands?
Please explain your response.

Problem 6: An experiment was conducted to examine the effect of age on heart rate when a individual is subjected to a certain amount of exercise. Ten male subjects were randomly selected from four age groups: 10-19, 20-39, 40-59 and 60-69. Each subject walked a treadmill at a fixed grade for a period of 12 minutes and the increases in heart rate (the difference between the before and after heart rate) was recorded in beats per minute. The data are shown in the table below. Does the data provide sufficient evidence to indicate a difference in mean increase in heart rate among the four age groups? Use $\alpha =0.05$

10-19	20-39	40-59	60-69
29	24	37	28
33	27	25	29
26	33	22	34
27	31	33	36
39	21	28	21
35	28	26	20
33	24	30	25
29	34	34	24
36	21	27	33
22	32	33	32

Problem 7: It has been suggested that treatment of a plastic used in optic lenses will improve wear. Four different treatments are to be tested. To determine whether any differences in mean wear exist among treatments, 28 castings were made from a single formulation of the plastic and seven casting were randomly assigned to each of the treatment groups. "Wear" was determined by measuring the increase in haze after 200 cycles of abrasion.

A	B	C	D
9.13	11.95	11.47	11.35
13.29	15.15	9.54	8.73
12.07	14.75	11.26	10
11.97	14.79	13.66	9.75
13.31	15.48	11.18	11.71
12.32	13.47	15.03	12.45
11.78	13.06	14.86	12.38

Is there evidence of a difference in mean wear among the four treatments? Use $\alpha =0.05$. Can you reject the null hypothesis?
Estimate the mean difference in haze increase between treatments B and C using a 99% confidence interval. Is there a discernible difference?
Find a 90% confidence interval for the mean wear for lenses receiving treatment A . If it is believed that ${{\mu }_{A}}=8.75$ for treatment A , based on your interval can you accept this claim.

Problem 8: Suppose a random sample of 15 families had the following annual income and savings. Using SPSS, answer the following:

Family	Income	Savings
1	22	2
2	18	2
3	17	1.6
4	27	3.2
5	30	3
6	21	2
7	23	1.9
8	28	3.1
9	15	1.5
10	20	2.5
11	16	1.8
12	22	2.1
13	21	2
14	30	3
15	15	1.4

Estimate the population regression line for savings. Also construct the confidence interval for $\beta $
Graph the points and a fitted line
If income is 25, what can you estimate savings be?
What is the null hypothesis? Can you reject the null hypothesis?

Price: $17.39

Solution: The downloadable solution consists of 10 pages, 739 words and 11 charts.
Deliverable: Word Document