Ch 4 pt 1 - Z scores

Question 1

Z scores

Answer 1

can be used to describe any one score in a distribution relative to the other scores in the distribution

The # of SD’s a score is above/below the mean is called a z score.

Written to 2 decimal places

A positive z score means the score is above the mean. A negative one is below.

Question 2

Standard scores

Answer 2

When we use SD units to determine how far above/below the mean a score falls, this is what we refer as standard scores, as we are standardizing scores in terms of how many SD’s they are away from the mean

Question 3

Properties of Z Scores

Answer 3

1. Sum of a set of Z scores is always 0.
2. The mean of the distribution of 2 scores is 0, because as we learned, the sum of a distribution of 2 scores=0
3. The SD of a set standardized scores is always 1, because the deviation scores have been divided by the SD