A test is used to access readiness for college. In a recent year, the mean test score was 20.7 and the standard deviation was 4.5. Identify the test scores that are significantly low or significantly high.

We can calculate limits required with the condition of 2 deviations from the mean and we got:

If a value is lower than 11.7 we can consider it as too low

If a value is Higher than 29.7 we can consider it as too high

Step-by-step explanation:

For this case we know the following info:

represent the mean

And we want to find scores that are significantly low or significantly high

We can calculate limits required with the condition of 2 deviations from the mean and we got:

If a value is lower than 11.7 we can consider it as too low

If a value is higher than 29.7 we can consider it as too high

the simplified form is

step-by-step explanation:

we want to simplify the expression,

let us change the middle bar to a normal division sign to obtain,

we multiply the first fraction by the reciprocal of the second fraction to obtain,

we factor to obtain,

we cancel the common factors to get,

we simplify to get,

the correct answer is b