Question

For a normal distribution curve with a mean of 19 and a standard deviation of 6, which range of the variable defines an area under the curve corresponding to a probability of approximately 68%?

a. from 16 to 22
b. from 13 to 25
c. from 19 to 31
d. from 7 to 31

Answer 1

68.2% is the area that's ± one standard deviation on either side of the mean,
so is would be 19 ± 6, which is 13 to 25 or B.

Answer 2

Thanks

Answer 3

No problem