Question

The annual snowfall in a town has a mean of 39 inches and a standard deviation of 10 inches. Last year there were 64 inches of snow. How many standard deviations from the mean is that? 0.45 standard deviations below the mean 0.45 standard deviations above the mean 2.50 standard deviations above the mean 2.50 standard deviations below the mean

Answer 1

2.50 standard deviations above the mean

Explanation:

The z-score measures how many a measure is above or below the mean. If the score is positive it is above the mean. If it is negative, it is below. The zscore is given by

`Z = (X - \mu)/(\sigma)`

In which
`\mu` is the mean and
`\sigma` is the standard deviation.

In this problem, we have that:

`\mu = 39, \sigma = 10`

Last year there were 64 inches of snow. How many standard deviations from the mean is that?

This is Z when X = 64. So

`Z = (X - \mu)/(\sigma)`

`Z = (64 - 39)/(10)`

`Z = 2.5`

So the correct answer is:

2.50 standard deviations above the mean