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A city mayor in Michigan is planning the number of new snow plows he must purchase to remove the snow next winter. The
average snowfall in the past 10 years has been normally distributed with a mean of 112 inches and a standard deviation of
14 inches. What amount, in inches, separates the lowest 20% of the means of yearly snowfall in the past 10 years from the
highest 80%?

Respuesta :

The amount that separates the lowest 20% of the means of yearly snowfall in the past 10 years from the highest 80% is 23.57 inches.

Given mean of 112 inches, standard deviation of 14 inches.

We are required to find the amount that separates the lowest 20% ofthe means of yearly snowfall in the past 10 years from the highest 80%.

a) Bottom 20% would have a z score of -0.8416.

b) Top 80% would have a z score of 0.842.

Use the z formula to find the raw score.

z=(X-m)/sd

X=the raw score

m= mean

sd=standard deviation

Putting the value of low score.

-0.8416=(X-112)/14

X=-11.7824+112

=100.2176

Putting the values of high score.

0.842=(X-112)/14

X=123.788

The amount that seprates the lowest from highest is 123.788-100.2176

=23.57 inches.

Hence the amount that separates the lowest 20% of the means of yearly snowfall in the past 10 years from the highest 80% is 23.57 inches.

Learn more about z test at https://brainly.com/question/14453510

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