For males in a certain town, the systolic blood pressure is normally distributed with a mean of 115 and a standard deviation of 6. Using the empirical rule, determine the interval of systolic blood pressures that represent the middle 68% of males.
The middle 68% of males would fall within one standard deviation of the mean on either side.
So, we would need to find the interval that is one standard deviation below and one standard deviation above the mean.
One standard deviation below the mean: 115 - 6 = 109
One standard deviation above the mean: 115 + 6 = 121
Therefore, the interval that represents the middle 68% of males would be 109 to 121.