Question

the lifespans of seals in a particular zoo are normally distributed. the average seal lives 13.8 years; the standard deviation is 3.2 years. use the empirical rule (68 - 95 - 99.7%) to estimate the probability of a seal living less than 7.4 years. \boxed{}%

Explanation:

Step1: Calculate z-score for 7.4

$z = \frac{7.4 - 13.8}{3.2} = -2$

Step2: Apply empirical rule

95% within $\mu \pm 2\sigma$, so 5% outside. Half below $\mu - 2\sigma$: $5\%/2 = 2.5\%$

Answer:

2.5