Question

The weights of the fish in a certain lake are normally distributed with a mean of 19 lbs and a standard deviation of 6. If 25 fish are randomly selected, what is the probability that the mean weight will be greater than 17.2 lbs

Answer 1

0.93319

Explanation:

We solve the question using the z score formula

z = (x-μ)/σ/√n where

x is the raw score = 17.2 lbs

μ is the population mean = 19 lbs

σ is the population standard deviation = 6

n is the random number of samples = 25 fishes

Greater than sign = >

For x > 17.2 lbs

z = 17.2 - 19/6/√25

z = 17.2 - 19/ 6/5

z = 17.2 - 19/1.2

z = -1.5

Probability value from Z-Table:

P(x<17.2) = 0.066807

P(x>17.2) = 1 - P(x<17.2)

P(x>17.2) = 1 - 0.066807

P(x>17.2) = 0.93319

Therefore, that the probability that the mean weight will be greater than 17.2 lbs is 0.93319