Question

The confidence interval for the difference in means

		6.2 - 15.7
		4.4 - 13.9
		5.6 - 15.1
	Confidence Interval for the Difference Between Two Independent Means Find the confidence interval for the difference in the average monthly egg production of free range versus caged hens at the 95% confidence level using a sample of 25 free range and 25 caged hens. GIVEN: Pooled Std Dev = 8.334 Free Range Caged 38 41 39 31 32 34 43 32 46 50 45 26 55 28 49 31 42 38 40 41 63 33 62 32 61 33 61 53 43 31 43 43 51 36 33 47 39 39 64 28 52 40 30 47 46 42 39 37 52 46	3.2 - 12.7

Answer 1

Formula for Confidence Interval for Difference in two Population means

: Sample Size of Sample 1: free range hens : Sample Size of Sample 1: caged hens : Sample Mean of Sample 1 : Sample Mean of Sample 2 sp : Pooled standard deviation Free Range:x1 Caged:x2 38 41 39 31 32 34 43 32 46 50 45 26 55 28 49 31 42 38 40 41 63 33 62 32 61 33 61 53 43 31 43 43 51 36 33 47 39 39 64 28 52 40 30 47 46 42 39 37 52 46 Total 1168 939 Sample mean for sample 1 : Sample mean for sample 2 : sp : Pooled standard deviation = 8.334 Given : Sample Size of Sample 1 25 : Sample Size of Sample 2 25 : Sample Mean of Sample 1 46.72 : Sample Mean of Sample 2 37.56 Confidence Level 95% (= 100-95/100=5/100 ) = 0.05 0.05 /2 (=0.05/2=0.025) 0.025 48 2.0106 Confidence Interval for Difference in two Population means