Question

  Drug A was prescribed for a random sample of 12patients complaining of insomnia. An independent random sample of 16patients with the same complaint received drugB.The number of hours of sleep experienced during the second night after treatment began were as follows:

A: 3.5, 5.7, 3.4, 6.9, 17.8, 3.8, 3.0, 6.4, 6.8, 3.6, 6.9, 5.7

B: 4.5, 11.7, 10.8, 4.5, 6.3, 3.8, 6.2, 6.6, 7.1, 6.4, 4.5, 5.1, 3.2, 4.7, 4.5, 3.0

Construct a 95 percent confidence interval for the difference between the population means. Assume that the population variances are equal.

Answer 1

	A( X )		B( Y )
	3.5	6.8906	4.5	1.7062
	5.7	0.1806	11.7	34.7369
	3.4	7.4256	10.8	24.938
	6.9	0.6006	4.5	1.7062
	17.8	136.3056	6.3	0.2438
	3.8	5.4056	3.8	4.0248
	3	9.7656	6.2	0.1551
	6.4	0.0756	6.6	0.6301
	6.8	0.4556	7.1	1.6739
	3.6	6.3756	6.4	0.3526
	6.9	0.6006	4.5	1.7062
	5.7	0.1806	5.1	0.4987
			3.2	6.7923
			4.7	1.2237
			4.5	1.7062
			3	7.87
Total	73.5	174.2622	92.9	89.9695

Mean

Standard deviation

Mean

Standard deviation

Confidence interval is :-

Lower Limit =
Lower Limit = -2.1836
Upper Limit =
Upper Limit = 2.8212
95% Confidence Interval is ( -2.1836 , 2.8212 )