Answer:
1)
66 - 80
2)
59 - 87
3)
53 - 94
standard deviation is a measure of how many data points different from the mean each individual data point is.
if the standard deviation is 7, the range is +7 and -7 68% of the time
the data will be within 2 standard deviations +14 -14 95% of the time
the data will be within 3 standard deviations +21 -21 99.7% of the time