Z-scores And The Standard Distribution

Question 1

What is a raw score?

Answer 1

Participants score or unchanged score.

Question 2

How is a raw score transformed into a z-score?

Answer 2

Raw score - M
_______________
SD

Question 3

In any distribution of z-scores what is the mean?

Answer 3

Always 0

Question 4

In any distribution of z-scores what is the standard deviation?

Answer 4

Always 1

Question 5

What are z-scores expressed in?

Answer 5

Standard deviation units

Question 6

What type of transformation is z-scores?

Answer 6

Linear transformation. On a graph they stay at the same points just in standard deviations units.

Question 7

What is normal distribution of z-scores called?

Answer 7

Standard normal distribution (when it’s shaped like a bell)

Question 8

What are the percentages of standard normal distribution of a score falling between -1 and +1

Answer 8

68.26%

Question 9

What are the percentages of standard normal distribution of a score falling between -2 and +2

Answer 9

95.46%

Question 10

What are the percentages of standard normal distribution of a score falling between -3 and +3

Answer 10

99.73%

Question 11

What are the percentages of standard normal distribution of a score at 1 SD?

Answer 11

34.13%

Question 12

What can standard normal distribution be used for?

Answer 12

• knowing the percentile of a score (the percent of all scores below the score) in a variable
• comparing a score on a variable with a score on another variable
• knowing which score on a variable is at a specific percentile