Question

3) The Acme Candy Company claims that 60% of the jawbreakers it produces weigh more than 0.4 ounces. Suppose that 800 jawbreakers are selected at random from the production lines. Use the Range Rule of Thumb to determine whether it is statistically significant for this sample of 800 to contain 494 jawbreakers that weigh more than 0.4 ounces? Consider as significant any result that differs from the mean by more than 2 standard deviations. Show all work (using Range Rule of Thumb) required to obtain your answer. Clearly state all important values involved.

Answer 1

Question 3

Here The proportion of employees who have borrowed from their plan is equal to the 22% reported nationwide. The difference is due to chance.

Here range rule of thumb say that if the value is outside the 2 standard deviation away from the expected mean than it is significant.

Here expected number of jawbreakers out of 800 to weigh more than 0.4 ounces = 800 * 0.6 = 480

standard deviation of number of jawbrekers out of 800 to weigh more than 0.4 ounces = sqrt [800 * 0.6 * 0.4] = 13.86

so here range of values that are significant = 480 +- 2 * 13.86 = (452.3, 507.7)

as the value of 494 is included in the confidenne interval that means the claim of the comapny is correct and it is not statistically significant for the sample to contain 494 jawbreakers that weigh more than 0.4 ounces.