Question

In a study of household recycling practices, 30 randomly selected households had their recycling output measured in both pounds of paper waste and pounds of plastic waste. The StatCrunch data set for this question contains the two measurements for each household. Use the data to construct a 95% confidence interval estimate of the difference between the mean weight of paper waste for a household and its mean weight of plastic waste. Use paper waste as Sample 1. Round each of your answers to three decimal places; add trailing zeros as needed. The 95% confidence interval estimate is lb < µ1 - µ2 < lb.

Paper    Plastic

15.09   9.11   ""
6.98   2.65   ""
12.32   11.17   ""
11.42   12.81   ""
12.73   14.83   ""
13.61   8.95   ""
11.36   10.25   ""
5.86   3.91   ""
9.19   3.74   ""
14.33   6.43   ""
6.44   8.4   ""
6.67   6.09   ""
3.27   0.63   ""
16.08   14.36   ""
7.72   3.86   ""
7.98   6.09   ""
9.55   9.2   ""
9.45   3.02   ""
6.38   8.82   ""
6.05   2.73   ""
9.41   3.36   ""
6.33   3.86   ""
20.12   18.35   ""
16.39   9.7   ""
6.96   7.6   ""
13.31   19.7   ""
11.08   12.47   ""
2.41   1.13   ""
8.82   11.89   ""
12.43   8.57   ""

Answer 1

Solution : 95% confidence interval for mean difference of plastic and paper is

(-52.774 , 164.691 )

Explanation :

				Paper	Plastic
				15.09	9.11
				6.98	2.56
				12.32	11.17
				11.42	12.81
				12.73	14.83
	xb	64.07833		13.61	8.95
	yb	8.119667		11.36	10.25
	s1	297.4811		5.86	3.91
	s2	4.898804		9.19	3.74
				14.33	6.43
	sp	210.3794		6.44	8.4
				6.67	6.09
				3.27	0.63
				16.08	14.36
Lower bound	-52.7741			7.72	3.86
Upper bound	164.6914			7.98	6.09
				9.55	9.2
				9.45	3.02
T(alfa)	2.001717			6.38	8.82
				6.05	2.73
				9.41	3.36
				6.33	3.86
				20.12	18.35
				1639	9.7
				6.96	7.6
				13.31	19.7
				11.08	12.47
				2.41	1.13
				8.82	11.89
				12.43	8.57