Question

A set of data has a mean of 12 and a standard deviation of 3. A data point of the set has a z-score of 1.3. What does a z-score of 1.3 mean?

Answer 1

B. The data point is 1.3 standard deviations away from 12.

Answer 2

A z-score tells you how many standard deviations a point is from the mean.

`z = (x - mean)/(std dev)`
Working backwards with this formula,

`x = z*std dev + mean \\ \\ x = 1.3*3 + 12 \\ \\ x = 15.9`

So the data point is 15.9 and is 1.3 std deviations from the mean of 12.

Hope this helps.