Question

The population mean weight of a candy is 10 grams with a standard deviation of 2 grams. A sample of 100 candies is taken. What is the probability that the sample mean is 10.5 grams or lower?

Answer 1

We need to compute $P(X \le 10.5)$. The corresponding z-value needed to be computed are:

$Z = \frac{\bar X- \mu}{\sigma/\sqrt n}= \frac{ 10.5-10}{ 2/\sqrt{100}} = 2.5$,

using table, p=0.99379