An accounting firm is planning for the next tax preparation season. From last year's returns, the firm collects a systematic random sample of 100 filings. The 100 filings showed an average preparation time of 90 minutes with a standard deviation of 140 minutes. 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 average 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 for making inferences about the average time.

An Accounting Firm Is Planning for the Next Tax Preparation