Question

10) A competency test has scores with a mean of 255 and a standard

Answer 1

Answer:

The percentage of scores higher than 72 is 99.85%

Explanation:

The empirical rule states that about 68% of observations falls within the first standard deviation (µ ± σ), 95% within the first two standard deviations (µ ± 2σ), and 99.7% within the first three standard deviations (µ ± 3σ)

We can use the relationship below

255-σ(61)=72

61σ=255-72

61σ=183

σ=3

The area is as shaded below

The percentage of scores higher than 72 is 99.7%+0.15%=99.85%