Question

Lee's first history exam score is +2 standard deviations from the mean in a normal distribution. The test has a mean of 65 and a standard deviation of 5. Lee's percentile rank would be approximately _____.

a.97.5%

b.65 %

c.75 %

d.none of the above

Answer 1

For normal distribution, about 95% of the observations lies within 2 standard deviations of the mean. Therefore, (1 - 0.95)/2 = 2.5% of the observations lies above 2 standard deviations from the mean. Therefore Lee's Percentile rank here is computed as:

= 1 - 2.5%

= 97.5%

Therefore the percentile rank here is 97.5%