Bones Brothers & Associates prepare individual tax returns. Over prior years, Bones Brothers has maintained careful records regarding the time to prepare a return. The mean time to prepare a return is 90 minutes and the standard deviation of this distribution is 14 minutes. Suppose 100 returns from this year are selected and analyzed regarding the preparation time. What assumptions do you need to make about the shape of the population distribution of all possible tax preparation times to make inferences about the mean time to complete a tax form?
A) The population distribution is skewed to the right.
B) The population distribution is skewed to the left.
C) The population distribution is normal.
D) The shape of the population distribution does not matter.

Question

Quizplus · Accepted Answer

The Central Limit Theorem states that the sampling distribution of the sample mean will be approximately normal regardless of the shape of the population distribution, given a sufficiently large sample size (usually n > 30). Since the sample size here is 100, the shape of the population distribution does not matter.

Bones Brothers & Associates Prepare Individual Tax Returns