Question

Mean is 90 minutes.

Standard deviation is15 minutes.

68% is between which two time intervals?

99.7% of the people work out for no more than ____________ minutes.

Answer 1

Given

= 90, = 15

According to Emperical rule(68-95-99.7) rule,

Approximately, 68% of the data falls in 1 standard deviation of the mean.

That is 68% is between interval ( - , + ) =( 90-15, 90+15) = ( 75,105)

That is 68% is between time interval (75,105)

Approximately, 99.7% data falls in 3 standard deviation of the mean.

We have to find upper bound of the interval such that 99.7% pf the people work out for no more that value.

3 standard deviation above the mean = + 3 = 90 + 3 * 15 = 135

99.7% of the people work out for no more than 135 minutes.