please help with this question

People were polled on how many books they read the previous year. Initial survey results indicate that s = 11.1 books. Complete parts (a) through (cl) below. 3 Click the icon to view a partial table of critical values. 0 Partial Critical Value Table - X Level of Condence, Area in Each Tail, Critical Value, 2\"\" (1 a) . 100% 90% 1 .645 95% 1 .96 99% 2.575 (d) How many subjects are needed to estimate the mean number of books read the previous year within four books with 99% confidence? This 99% confidence level requires subjects. (Round up to the nearest subject.)