Question

Suppose the temperature of a cup of coffee is normally distributed with a mean of 142 degrees F.

If a cup of coffee has a z score of -0.50, which of the following is true?

Select one:

a. 30.85% of cups are at a lower temperature

b. 93.32% of cups are at a lower temperature

c. 95% of cups are at a lower temperature

d. 5% of cups are at a higher temperature

Answer 1

Answer)

As the data is normally distributed we can use standard normal z table to estimate the answers

From z table, p(z<-0.5) = 0.3085 = 30.85%

That is 30.85% of cups are at a lower temperature