Ana earned a score of 940 on a national achievement test that was normally distributed. The mean test score was 850 with the standard deviation of 100. If 1000 students took the test, how many scored below Amanda? Use z-table
http://www.intmath.com/counting-probability/z-table.php

Question

Ana earned a score of 940 on a national achievement test that was normally distributed. The mean test score was 850 with the standard deviation of 100. If 1000 students took the test, how many scored below Amanda? Use z-table
http://www.intmath.com/counting-probability/z-table.php

kropot72 · Answer

The z-score for 940 is found by using this formula
$$z=\frac{X-\mu}{\sigma} =\frac{940-850}{100}=you\ can\ calculate$$
When you have the z-score, use the table to find the cumulative probability. Then multiply the cumulative proability by 1000 to find how many scored below Amanda.