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 $\mu + 2 \sigma$.
-The Acme Candy Company claims that 60% of the jawbreakers it produces weigh more than .4 ounces. Suppose that 800 jawbreakers are selected at random from the production lines. Would it be unusual for this sample of 800 to contain 528 jawbreakers that weigh more than .4 ounces?
A)No
B)Yes

Question

Quizplus · Accepted Answer

The expected number of jawbreakers weighing more than 0.4 ounces is $0.6 \times 800 = 480$. The standard deviation is $\sqrt{800 \times 0.6 \times 0.4} = \sqrt{192} \approx 13.86$. The range for usual values is $480 \pm 2 \times 13.86$, which is approximately $452.28$ to $507.72$. Since 528 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