# Computing Z-Scores #2

#### sophieb

##### New Member
The following data represent the number of inches of rain in Chicago, Illinois, during the month of April for 20 randomly selected years.

2.47, 3.97, 3.94 ,4.11, 1.14, 4.02, 3.41, 1.85, 5.22, 0.97, 6.14, 2.34, 3.48, 4.77, 2.78, 4.00, 6.28, 5.50, 7.69, 5.79

Compute the z-score corresponding to the rainfall in 1971, 0.97 inches. Interpret this result.

#### JohnM

##### TS Contributor
Compute the mean and standard deviation of the data set, then the z score for 0.97:

Z = (0.97 - u) / s

u = mean of the data set
s = standard deviation of the data set

The interpretation would be whether it was above or below average, and how many standard deviations it is away from the mean.

#### sophieb

##### New Member
thanks for the help. I'm having trouble knowing where to plug in the data to the formula but I have it figured out.