Question

the mean of a set of data is 40 pounds and the standard deviation is 8 pounds. what is the z - score of an object with a weight of 30 pounds?
-0.56
0.56
1.25
8.75
-0.8
-1.25

Explanation:

Step1: Recall the z - score formula

The z - score formula is \(z=\frac{x-\mu}{\sigma}\), where \(x\) is the data point, \(\mu\) is the mean, and \(\sigma\) is the standard deviation.

Step2: Substitute the given values into the formula

Given \(\mu = 40\), \(\sigma=8\), and \(x = 30\). Then \(z=\frac{30 - 40}{8}\).

Step3: Calculate the value of the z - score

\(z=\frac{30 - 40}{8}=\frac{-10}{8}=-1.25\)

Answer:

-1.25