I can't seem to understand S3 June 2009 question 2, I got 20.4 and 19.8 but the answer is 19.1 and 21.1. Please help.
The question:
The heights of a random sample of 10 imported orchids are measured. The mean height ofthe sample is found to be 20.1 cm. The heights of the orchids are normally distributed.
Given that the population standard deviation is 0.5 cm,
(a) estimate limits between which 95% of the heights of the orchids lie