(a) A sample of 954 adults in early 1987 found that 23% of them held shares. Given a UK adult population of 41 million and assuming a proper random sample was taken, find the 95% confidence interval estimate for the number of shareholders in the UK.

(b) A ‘similar’ survey the previous year had found a total of 7 million shareholders. Assuming ‘similar’ means the same sample size, find the 95% confidence interval estimate of the increase in shareholders between the two years.