Question

Suppose that diastolic blood pressure readings of adult males have a bell-shaped distribution with a mean of 84 mmHg and a standard deviation of 9 mmHg Using the empirical rule. what percentage of adult males have diastolic blood pressure readings that are greater than 102 mmHg? 

Suppose that grade point averages of undergraduate students at one university have a bell-shaped distribution with a mean of 2.62 and a standard deviation of 0.39 Using the empirical rule, what percentage of the students have grade point averages that are at least 3.4? Please do not round your answer.

Answer 1

Answer 1

We know that the distribution is normal.

According to the empirical rule, we know that:

68% of the data lies within 1 standard deviation of the mean.

95% of the data lies within 2 standard deviation of the mean.

99.7% of the data lies within 3 standard deviation of the mean.

102 is two standard deviations away from 84 towards the right. We know that 5% of the data lies outside 2 standard deviations; but since we need only the one tailed probability, the value is 2.5% or 0.025.

Answer 2

We know that the distribution is normal.

68% of the data lies within 1 standard deviation of the mean.

95% of the data lies within 2 standard deviation of the mean.

99.7% of the data lies within 3 standard deviation of the mean.

3.4 is two standard deviations away from 2.62 towards the right. We know that 5% of the data lies outside 2 standard deviations; but since we need only the one tailed probability, the value is 2.5% or 0.025.