Idkkkk how to do this problemmm

Question

If the mean score on a test is 60, the data are distributed normally, and the standard deviation is 5, what percentage of the test scores will be found between 55 and 60?

Answer 1

Here's what we know:

Normally distributed data

Mean test score = 60

Standard Deviation (SD) = 5

What percent of the scores will fall between 55 and 60?

Remember the normal bell curve? I can't draw it here, but it is bell shaped.

Do you remember the empirical rule? It has to do with percentages and standard deviations.

_____ % of data falls within 1 standard deviation

_____% of data falls within 2 standard deviations

_____% of data falls within 3 standard deviations

With a standard deviation of 5, and the mean score of 60, one standard deviation below would be 55. One standard deviation above would be 65.

So, _____% of data falls with 55 and 65 for this problem. We don't want to go to 65, so we only want half of that. So take this percent number and divide it by two.

Without giving you the answer, I hope you can figure it out from there. Let me know if you have questions.

(If you're still unsure, google "empirical rule" )

Cheers,

Margaret