Question

If data is normally distributed and has μ = 90 and o-10, what is the z-score for a data value of 75?

Answer 1

The z-score for this data is -1.5

Explanation:

Step 1: For the specified distribution and data point,

μ = 90, σ = 10, and x = 75 (given)

Step 2: We now apply the z-score formula:

z = x − μ / σ

z = 75 - 90 / 10

z = - 15 / 10

z = -1.5

We can take it a step further:

A z-score table shows the percentage of values (usually a decimal figure) to the left of a given z-score on a standard normal distribution

percentage of value = 0.0668