The data below gives the mean price (in cents) of a litre of regular gasoline at self-service filling stations at a sample of six urban centres in Canada in May 2014.

Urban area

Halifax

Saint John, NB

Thunder Bay

Winnipeg

Vancouver

Victoria

Price/litre

139.1

135.6

141.7

127.8

149.1

139.2

Urban areaPrice/litreHalifax139.1Saint John, NB135.6Thunder Bay141.7Winnipeg127.8Vancouver149.1Victoria139.2

Provide answers to the following to two decimal places.

Part (a)Find the sample mean (in cents).

Part (b)Find the sample standard deviation (in cents).

Part (c)Using the appropriate t distribution, find a 90% confidence interval for the mean gasoline price per litre across urban Canada in May 2014. Provide the upper and lower bounds for your confidence interval. (,)

Part (d)Would a 95% confidence interval be wider or narrower than the interval you found in Part (c)? Using the appropriate t distribution, find a 95% confidence interval for the mean gasoline price per litre across urban Canada in May 2014. Provide the upper and lower bounds for your confidence interval. (,)

The data below gives the mean price (in cents) of a litre of regular gasoline at self-service filling stations at a sample of six urban centres in Canada in May 2014. Urban area Price/litre Halifax 139.1 Saint John, NB 135.6 Thunder Bay 141.7 Winnipeg 127.8 Vancouver 149.1 Victoria 139.2 Provide answers to the following to two decimal places. Part (a) Find the sample mean (in cents). Part (b) Find the sample standard deviation (in cents). Part (c) Using the appropriate t distribution, find a 90% confidence interval for the mean gasoline price per litre across urban Canada in May 2014. Provide the upper and lower bounds for your confidence interval. ( Part (d) Would a 95% confidence interval be wider or narrower than the interval you found in Part (c)? Using the appropriate t distribution, find a 95% confidence interval for the mean gasoline price per litre across urban Canada in May 2014. Provide the upper and lower bounds for your confidence interval. (