Data given: Landline: n=14, X mean=16.5, S=13.18 Mobile: n=14, X mean=18.29, S=11.36 

(a) Find the 95% confidence intervals for the mean and variance of the monthly expenditure on mobile expenditure. 

(b) Find the 90% confidence intervals for the mean and variance of the monthly landline expenditure.

c) Examine whether the assumption that the company\'s customers spend, on average, the same amount on landline and mobile expenses is statistically supported.

(d) Consider whether the assumption that customers are spending on mobile a percentage of more than 55% of the total costs for both landline and mobile is statistically supported.

(e) Examine whether the hypothesis that customers spend on mobile and fixed telephony equal percentages of the total expenditure is statistically supported. (UNITS 5)