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 9.7 grams or lower?

Answer 1

Given : $\mu=10\\ \sigma=2$

n=100

Formula: $Z= \frac{\overline x-\mu}{\frac{\sigma}{\sqrt{n}}}$

Solution:

substitute the values to find z

$Z= \frac{9.7-10}{\frac{2}{\sqrt{100}}}$ −1.5

Using z table,$Pr( \overline x≤9.7)=Pr(Z≤−1.5)=0.0668$