Question

1. Positive behaviors on the normal curve has a mean of 12 and a standard deviation of 3, what are the z-scores and percentiles for the following outcomes?

1. 15 positive behaviors
2. 18 positive behaviors
3. 21 positive behaviors
4. 9 positive behaviors
5. 6 positive behaviors
6. 3 positive behaviors
7. 12 positive behaviors

Answer 1

As per the given information

We can compute the z-score using the formula

Percentile is the percentage of values that are lower than the given value of X.

a)

X = 15

Percentile of 15 positive behaviours = 84.134%

b) X = 18

Percentile of 18 positive behaviours = 97.725%

c) X = 21

Percentile of 21 positive behaviours = 99.865%

d) X = 9

Percentile of 9 positive behaviours = 15.866%

e) X = 6

Percentile of 6 positive behaviours = 2.275%

f) X = 3

Percentile of 3 positive behaviours = 0.135%

g) X = 12

Percentile of 12 positive behaviours = 50%