Determine if the outcome is unusual. Consider as unusual any result that differs from the mean by more than 2 standard deviations. That is, unusual values are either less than $\mu - 2 \sigma$ or greater than $\mu + 2 \sigma$.
-According to AccuData Media Research, 36% of televisions within the Chicago city limits are tuned to "Eyewitness News" at 5:00 pm on Sunday nights. At 5:00 pm on a given Sunday, 2500 such televisions are randomly selected and checked to determine what is being watched. Would it be unusual to find that 872 of the 2500 televisions are tuned to "Eyewitness News"?
A)No
B)Yes

Question

Quizplus · Accepted Answer

The mean number of televisions tuned to "Eyewitness News" is 0.36 * 2500 = 900. The standard deviation is $\sqrt{0.36 * 0.64 * 2500} = 12$. So, the unusual values are less than 900 - 2 * 12 = 876 or greater than 900 + 2 * 12 = 924. Since 872 is less than 876, it is not unusual.

Determine If the Outcome Is Unusual μ−2σ\mu - 2 \sigmaμ−2σ Or Greater Than

Determine If the Outcome Is Unusual $\mu - 2 \sigma$ Or Greater Than