Question

The weight of laboratory mice follows a normal distribution, with a mean of 0.68 ounce and a standard deviation of 0.02 ounce. What percentage of the mice weigh between 0.62 ounce and 0.74 ounce?

A.99.7%
B.95%
C.68%
D.47.5%
E.34%

Answer 1

A.99.7%

Explanation:

Calculate each z-score.

z = (x − μ) / σ

z = (0.74 − 0.68) / 0.02

z = 3

z = (x − μ) / σ

z = (0.62 − 0.68) / 0.02

z = -3

You can use a z-score table, or use the empirical rule.

P(-3 < z < 3) = 99.7%.