Find the standard deviation of the data summarized in the given frequency distribution.
-A weight of 220 pounds among a population having a mean weight of 161 pounds and a standard deviation of 23.5 pounds.
A)2.5; unusual
B)-2.5; not unusual
C)58.8; unusual
D)2.5; not unusual

Question

Quizplus · Accepted Answer

To find how unusual the weight of 220 pounds is within this population, we calculate the z-score using the formula $z = \frac{X - \mu}{\sigma}$, where $X$ is the value in question, $\mu$ is the mean, and $\sigma$ is the standard deviation. Plugging in the given values: $z = \frac{220 - 161}{23.5} = 2.5$. A z-score of 2.5 is considered unusual because it is more than 2 standard deviations away from the mean.

Find the Standard Deviation of the Data Summarized in the Given