Question

use the range rule of thumb to identify the values that are significantly low, the values that are signficantly high, and the values that are neither significantly low nor significantly high.
a test is used to assess readiness for college. in a recent year, the mean test score was 19.7 and the standard deviation was 4.8. identify the test scores that are significantly low or significantly high.
what test scores are significantly low? select the correct answer below and fill in the answer box(es) to complete your choice.
a. test scores that are between and . (round to one decimal place as needed. use ascending order.)
b. test scores that are less than 10.1. (round to one decimal place as needed.)
c. test scores that are greater than . (round to one decimal place as needed.)
what test scores are significantly high? select the correct answer below and fill in the answer box(es) to complete your choice.
a. test scores that are greater than (round to one decimal place as needed.)
b. test scores that are between and . (round to one decimal place as needed. use ascending order.)
c. test scores that are less than (round to one decimal place as needed.)

Explanation:

Step1: Recall range - rule - of - thumb

Significantly low values are $\mu - 2\sigma$ or lower, and significantly high values are $\mu+2\sigma$ or higher, where $\mu$ is the mean and $\sigma$ is the standard deviation.

Step2: Calculate significantly low value

Given $\mu = 19.7$ and $\sigma = 4.8$. Significantly low value is $\mu - 2\sigma=19.7-2\times4.8=19.7 - 9.6 = 10.1$.

Step3: Calculate significantly high value

Significantly high value is $\mu + 2\sigma=19.7+2\times4.8=19.7 + 9.6 = 29.3$.

Answer:

What test scores are significantly low?
B. Test scores that are less than 10.1.
What test scores are significantly high?
A. Test scores that are greater than 29.3.