An electronics retailer believes that,at most,40% of their cell phone inventory was sold during November. The retailer surveyed 80 dealers and found that 38% of the inventory was sold. Since 38% is less than 40%,is this difference of 2 percentage points sampling error or a significant difference? Test at the 0.05 level. The computed z = −0.37.
A)The 2% is a significant difference.
B)We cannot determine if the 2% is a significant difference.
C)There is not enough information to reach a conclusion.
D)None of the other answers apply.

Question

Quizplus · Accepted Answer

The computed z-score of −0.37 is not significant enough to reject the null hypothesis that the proportion sold is equal to or less than 40%. Therefore, the difference of 2 percentage points is likely just due to sampling error and not a significant difference.

An Electronics Retailer Believes That,at Most,40% of Their Cell Phone