Probability and Z-Scores

Find the Z-score.

Mean = 22

Standard Deviation: 3.1

x = 29

• 2.26

• 16.45

• -2.26

• 1.26

Find the Z-score.

Mean = 21

Standard Deviation: 1.3

x = 22

• 0.77

• 5.33

• 1.07

• 1.26

Find the Z-score.

Mean = 27

Standard Deviation: 1.4

x = 11

• -11.43

• 7.85

• -2.33

• 4.16

Find the z-score.

Mean = 38

Standard Deviation: 1.2

x = 42

• 3.33

• -3

• 3.03

• -3.33

Find the value of x.

Z-score = -2.2

mean = 25

Standard Deviation: 7

• 9.6

• -36

• 5.2

• 23.46

What is the purpose of z-scores?

• to describe the exact location of a score within a distribution

• to find the mean of the distribution

• to describe the shape of the distribution

• to find the standard deviation of the distribution

What is the formula to find the z-score for population?

• z=X-M

• z=σ-M/μ

• ^z/M=μ

• z=X-μ/σ

How to transform z-scores to X values for sample?

• X=μ+zσ

• X=M+zs

• μ=X+zσ

• σ(z)-M=s

The sign of the z-score indicates whether the location is above(positive) or below(negative) the mean.

• True

• False

Find the z-score value corresponding if the location is below the mean by 2 standard deviations

• +2.00

• -2.00

• +1.25

• -1.00