Question

In a particular year, the mean score on the ACT test was 19.6 and the standard deviation was 5.2. The mean score on the SAT mathematics test was 546 and the standard deviation was 126. The distributions of both scores were approximately bell-shaped. Round the answers to at least two decimal placesFind the z-score for an ACT score of 26. The Z-score for an ACT score of 26 is ______ .

Answer 1

0.11

Explanation:

Let the random variable score, X = 26; mean, ∪ = 19.6; standard deviation, α = 5.2

By comparing P(0≤ Z ≤ 26)

P(Z ≤ X - ∪/α) = P(Z ≤ 26 - 19.6/5.2)

= P(Z ≤ 1.231)

Using Table: P(0 ≤ Z ≤ 1) = 0.39

P(Z > 1) = (0.5 - 0.39) = 0.11

∴ P(Z > 26) = 0.11