I have to find out someones mark on a couple tests
Test 1: Mean=77 SD=3.9
Test 2: Mean=83 SD=3.9
Test 3: Mean=77 SD=7.4
If someone can show me how to do one of them I can probably do the rest.
I know there has to be something with a bell chart and 68% but not really sure of the formula or steps.
Thanks in advance
edit: I added 2x(3.9) to 77 and got 84.8% which was the answer
Then for test #2 I did 88-3.9 which was the answer, how does the adding and subtracting of standard deviations work like this?
Test 1: Mean=77 SD=3.9
Test 2: Mean=83 SD=3.9
Test 3: Mean=77 SD=7.4
If someone can show me how to do one of them I can probably do the rest.
I know there has to be something with a bell chart and 68% but not really sure of the formula or steps.
Thanks in advance
edit: I added 2x(3.9) to 77 and got 84.8% which was the answer
Then for test #2 I did 88-3.9 which was the answer, how does the adding and subtracting of standard deviations work like this?
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