Chp 8 - Q. 8.7 What is the approximate probability that the mean of a sample of 10 observations from a Beta(10,10) random variable falls between 0.48 and 0.52? Here the mean = 0.5 and variance = 0.011904761 I approximated this as N(0.5,0.012/10) and got the answer 0.43629 The solution in the study material approximated N(0.5,0.01190/10) and their answer is 0.43794. Would my answer be considered wrong? If yes then how do I figure out when to round off and when to not. This has happened many a times throughout my CT3 course. I apply the concepts and formulas properly but end up getting inaccurate answers.
Since you rounded it to only 2 SF you can only hope for your answer to be correct to 2 SF. Examiners look at at least 3 SF. So in this case you would not get the marks. The best thing to do is to store the full answer in your calculator's memories and use those when standardising.
