Question

On a standardized test with a normal distribution, the mean was 64.3 and the standard deviation was 5.4. What is the best approximation of the percent of scores that fell between 61.6 and 75.1? 1) 38.2% 2) 66.8% 3) 68.2% 4) 95%

Answer 1

4.

Explanation:

To find the number of standard deviations 75.1 and 61.5 are above and below the mean, find the difference between these two numbers and the mean, then divide by the standard deviation 5.4:

`(75.1-64.3)/5.4=2 sd`

The empirical rule states that 95% of data fall between 2 standard deviations from the mean.

Thus, the answer is 4.