Question

use the range rule of thumb to identify the values that are significantly low, the values that are significantly 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 19.4 and the standard deviation was 4.9. identify the test scores that are significantly low or significantly high. what test scores are significantly high? select the correct answer below and fill in the answer box(es) to complete your choice.

Explanation:

Step1: Recall the range rule of thumb formula

The range rule of thumb states that values are significantly low if \(x<\mu - 2\sigma\) and significantly high if \(x>\mu + 2\sigma\), where \(\mu\) is the mean and \(\sigma\) is the standard deviation. Given \(\mu = 19.4\) and \(\sigma=4.9\).

Step2: Calculate the significantly high value

For significantly high values, use the formula \(x=\mu + 2\sigma\). Substitute \(\mu = 19.4\) and \(\sigma = 4.9\) into the formula:

$$x=19.4+2\times4.9$$

$$x=19.4 + 9.8$$

$$x=29.2$$

Answer:

A. Test scores that are greater than \(29.2\)