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 919 of the
2500 televisions are tuned to "Eyewitness News"?
A) Yes
B) No

Question

Quizplus · Accepted Answer

The mean number of televisions tuned to "Eyewitness News" is 0.36 * 2500 = 900. The standard deviation is $\sqrt{0.36 * 0.64 * 2500} = 30$. So, the range of usual values is 900 +/- 2 * 30 = 840 to 960. Since 919 is within this range, 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