a) Banting is believed to reduce weight when done for a minimum of 10 days. A

random sample of 5 ladies were weighed before and after Banting. The data is

displayed on a table below.

Person Weight before Weight After

1 85 82

2 96 90

3 105 95

4 78 90

5 120 110

Construct a 95% for the difference in mean weight. [8 Marks]

b) Suppose you want to know the internet speed of two different mobile networks.

Network X Network Y

Sample size 12 15

Sample Mean 25 19

Sample std dev 60 50

Assuming that the population is normally distributed with equal variances.

Construct a 95% for the difference in mean internet speed. [6 Marks]

c) In a random sample, 70 of 100 men and 16 of 50 women are professional

footballers. Form a 90% confidence interval for the difference between the

proportion of men and the proportion of women who are professional footballers.

[6marks]

[TOTAL: 20 MARKS]Page 4 of 14