Question

1. You have been asked to continue your analysis of the ages of the supporters of the candidate with whom you have been consulting. One of the factors that need to be studied is the variability in the ages of those persons that have pledged their support to the candidate. In order to complete this task, you select a random sample of supporters and record their ages. This data is shown in appendix one below. At both the 2% and the 5% levels of significance, does the standard deviation in the ages of the supporters of the candidate differ from 10 years? Also, find a 98% confidence interval and a 95% confidence interval for the variance and standard deviation in the ages of the supporters of the candidate. Provide explanations of the meanings of these intervals as a part of your work.

Appendix One:

66       39       38       55       58       42       19       44       47       45       50

51       56       32       34       49       70       66       62       35       38       44

46       48       41      

Answer 1

Following table shows the calculations for mean and SD:

	X	(X-mean)^2
	66	361
	39	64
	38	81
	55	64
	58	121
	42	25
	19	784
	44	9
	47	0
	45	4
	50	9
	51	16
	56	81
	32	225
	34	169
	49	4
	70	529
	66	361
	62	225
	35	144
	38	81
	44	9
	46	1
	48	1
	41	36
Total	1175	3404

---------------------------

For 2% level of significance:

------------------------------------------------------

For 5% level of significance:

-------------------------------------------------------------------

The 98% confidence interval:

-----------------------------------------------

----------------------------------------------------------------------------

The 95% confidence interval:

-----------------------------------------------------