The development engineer of a company making razors has been asked by the marketing department to compare the shaving times of the company’s standard razor and deluxe razor.
The development engineer records the time,
X
, it takes him to shave, on seven mornings, using a standard razor. The times, in seconds, were: 217, 210, 254, 237, 232, 228, 243
His assistant volunteers to test the deluxe razor over six mornings and produces the following times,
Y
, measured in seconds: 186, 219, 168, 202, 191, 184
(i) Determine the sample mean and standard deviation for Sample
X
and Sample
Y
. (Marks-4)
(ii) Determine a 95 per cent confidence interval of the difference between the two means. (Marks-4)
(iii) Does this confidence interval suggest that there is a difference between the two shaving times?