Question

The average test score of the class was an 80 and the standard deviation was 2. About 99% of the class would score between what 2 values?

Answer 1

74 and 86

Explanation:

We know that 99% of a data set is within 3 standard deviations from the mean.

The average test score is 80 so 99% of the data is

so the data is between 74 and 86.

Answer 2

Answer: 78 and 82.

Explanation:

We have been given that the average test score of the class was an 80 and the standard deviation was 2. We are asked to find two values between which 68% of class will score.

We know that in a normal distribution approximately 68% of the data falls within one standard deviation of the mean.

So 68% scores will lie within one standard deviation below and above mean that is

Upon substituting our given values, we will get

Therefore, about 68% of the class would score between 78 and 81 and option B is the correct choice.

Step-by-step explanation: Hope this helps :D