Question

The weights in pounds of the 18 men on the crew teams at Oxford and Cambridge universities are given. (SHOW YOUR WORK)

Cambridge: 188.7 183.4 194.5 185.0 214.0 203.5 186.0 178.5 119.0

Oxford: 186.5 185.2 204.0 184.5 195.0 202.5 174.0 183.0 110.3

(a) The first eight values listed for Cambridge represent the weights of the eight rowers on the team. Assuming these eight men represent a random sample of all Cambridge crew team rowers over the years, compute a 90% confidence interval for the mean of that population. (Round your answers to two decimal places.) ( , )

(b) Make the same assumption as in part (a) about the weights of the first eight men in the Oxford sample. Compute a 90% confidence interval for the mean weight of Oxford rowers. (Round your answers to two decimal places.) ( , )

Answer 1

(a)

First we need to find the mean and SD of data:

	Cambridge, x	(x-mean)^2
	188.7	25.8064
	183.4	0.0484
	194.5	118.3744
	185	1.9044
	214	922.9444
	203.5	395.2144
	186	5.6644
	178.5	26.2144
	119	4175.7444
Total	1652.6	5671.9156

Sample size: n=9

The sample mean is:

The standard deviation :

Since there 9 data values in the sample so degree of freedom is df=9-1=8 and critical value of t for 90% confidence interval, using excel function "=TINV(0.10,8)" is 1.860.

The required confidence interval is

(b)

First we need to find the mean and SD of data:

	Oxford, x	(x-mean)^2
	186.5	35.2836
	185.2	21.5296
	204	549.4336
	184.5	15.5236
	195	208.5136
	202.5	481.3636
	174	43.0336
	183	5.9536
	110.3	4936.4676
Total	1625	6297.1024

Sample size: n=9

The sample mean is:

The standard deviation :

Since there 9 data values in the sample so degree of freedom is df=9-1=8 and critical value of t for 90% confidence interval, using excel function "=TINV(0.10,8)" is 1.860.

The required confidence interval is