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 Apply.

Question

Quizplus · Accepted Answer

Since the computed z-value is less than the critical value at the 0.05 level, we fail to reject the null hypothesis that the proportion of inventory sold is equal to or greater than 40%. Therefore, the difference of 2 percentage points is likely due to sampling error and not a significant difference.

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