Browsing as Guest. Progress, bookmarks and attempts are disabled.
Log in to track your work.
June 2015 p63 q5
3146
The heights of books in a library, in cm, have a normal distribution with mean 21.7 and standard deviation 6.5. A book with a height of more than 29 cm is classified as ‘large’.
(i) Find the probability that, of 8 books chosen at random, fewer than 2 books are classified as large.
(ii) n books are chosen at random. The probability of there being at least 1 large book is more than 0.98. Find the least possible value of n.
Solution
(i) To find the probability that a book is classified as large, we first standardize the height 29 cm using the normal distribution with mean 21.7 and standard deviation 6.5: