scores on an exam are normally distributed with a mean of 76 and a standard deviation of 10. in a group of 230 test, how many students score within one standard deviation of the mean?
a. about 156 students
b. about 187 students
c. about 78 students
d. about 115 students
please help:)

Question

amistre64 · Answer

aha!  stats..

amistre64 · Answer

<.......................76........................>
   -30  -20  -10      +10  +20  +30

amistre64 · Answer

one standard deviation of the means is abt 68% so;

230*.68 = our answer

amistre64 · Answer

abt. 156 is what I get