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 $\mu + 2 \sigma$
-A survey for brand recognition is done and it is determined that 68% of consumers have heard of Dull Computer Company. A survey of 800 randomly selected consumers is to be conducted. For such groups of 800,
Would it be unusual to get 634 consumers who recognize the Dull Computer Company name?
A) Yes
B) No

Question

Quizplus · Accepted Answer

The mean $\mu$ is 68% of 800, which is 544. The standard deviation $\sigma$ is $\sqrt{800 \times 0.68 \times 0.32}$, approximately 13.6. The range for usual values is 544 ± 2(13.6), or 517.8 to 570.2. Since 634 is outside this range, it is 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