Question

The number of hours per day a college student spends on homework has a mean of 6 hours and a standard deviation of 1.25 hours. Yesterday she spent 3 hours on homework. How many standard deviations from the mean is​ that? Round your answer to two decimal places.

Answer 1

Answer:

-2.4

Step-by-step explanation:

To calculate how many standard deviations you are from the mean you use Z-score, which is exactly that.

The formula is:

$Z-score = \frac{X-\mu}{\sigma} \\Where \\X: Value \\\mu: Mean \\\sigma: Standard\ deviation$

Replacing the information given in the formula you get:

$Z-score = \frac{3-6}{1.25} = -2.4$

She is -2.4 standard deviations from the mean or 2.4 to the left