Empirical Rule & Z-Score

What percentage of data is within 3 standard deviations

• 99.5%

• 68%

• 45%

• 99.7%

What percentage of data is within 2 standard deviations

• 68

• 95

• 99.7

• 2.35

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

Find the z-score.

Mean = 45

Standard Deviation: 2.1

x = 50

• 2.38

• 3.00

• 3.08

• 2.33

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 = 22

Standard Deviation: 3.1

x = 29

• 2.26

• 16.45

• -2.26

• 1.26

Find the z-score. Mean: 16 Standard Deviation: 4 x = 11

• -1.25

• +1.25

• 16

• 21

Find the z-score.

Mean: 22.8

Standard Deviation: 7

x = 20

• -0.4

• 17.2

• 22.04

• 32.5

If Gonzalo's score is 87, the class average is 82, and the SD is 4, what is Gonzalo's Z-score?

• -1.25

• +1.25

• +1.20

• +1.02