Question: The IRS examined approximately 1 of individual tax returns for
The IRS examined approximately 1% of individual tax returns for a specific year, and the average recommended additional tax per return was $19,150. Based on a random sample of 50 returns, the mean additional tax was $17,020. If the population standard deviation is $4080, is there sufficient evidence to conclude that the mean differs from $19,150 at α = 0.05? Does a 95% confidence interval support this result?
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