Question

The weights in pounds of the 18 men on the crew teams at Oxford and Cambridge universities are given.

Cambridge:	188.1	183.1	194.5	185.0	214.0	203.5	186.0	178.5	118.0
Oxford:	186.8	184.4	204.0	184.5	195.0	202.5	174.0	183.0	110.4

(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.) SHOW YOUR WORK
( ___________ , ____________ )

(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.) SHOW YOUR WORK
( _____________ , ___________ )

Answer 1

The summary statistic of the Cambridge and Oxford data is, Sample Size Mean SD Cambridge 183.411 26.917 n 9 Oxford 180.511 S2 28.018 n2 9 The t critical value at the 90% confidence level of the with 9-1 8 degrees of freedom is 1.860 Calculate the 90% confidence interval for the mean weight of Cambridge rowers

90%CI t critical 26.917 -183.411±1.860 9 183.411±16.684 =(166.727,200.095) -(166.73,200.10) (Round to 2 decimal place Hence, the required confidence interval is |(166.73<<200.10 b) Calculate the 90% confidence interval for the mean weight of Oxford rowers. S 90%CI t, vn critical 28.018 - 180.511 +1.860 180.511 17.367 (163.144,197.878) =(163.14,197.88) (Round to 2 decimal place) Hence, the required confidence interval is (163.14 <u<197.88)