The lifespans of gorillas in a particular zoo are normally distributed. the average gorilla lives 20.8 years; the

standard deviation is 3.1 years.

use the empirical rule (68 – 95 - 99.7%) to estimate the probability of a gorilla living less than 23.9

years.

The probability of a gorilla living less than 23.9 years is 0.84 (84%)

Step-by-step explanation:

We need to find the z-score of 23.9 years in the standard normal distribution of the lifespans of gorillas in a particular zoo.

z score can be calculated using the equation

where

Then

Empirical rule states that 68% of the lifespans lie within 1 standard deviation from the mean.

Half of it, % lies right side of 1 standard span of the mean.

Since lifespan less than mean is 50%, 50%+34% =84% lies less than z-score 1, that is the probability of a gorilla living less than 23.9 years.

$8

step-by-step explanation:

it is pretty much backwards.

you take the 4x2 multiply that, and that is = $8