Question

(a) The mean age at death is 15 years and the standard deviation is 7 years. What percentage of the dinosaurs' ages were within 1 standard deviation of the mean? (Answer as a whole number.)

Answer 1

68% of the dinosaurs' ages were within 1 standard deviation of the mean.

Explanation:

The Empirical Rule states that, for a normally distributed random variable:

68% of the measures are within 1 standard deviation of the mean.

95% of the measures are within 2 standard deviation of the mean.

99.7% of the measures are within 3 standard deviations of the mean.

What percentage of the dinosaurs' ages were within 1 standard deviation of the mean?

By the Empirical Rule, 68% of the dinosaurs' ages were within 1 standard deviation of the mean.