Question

You work for a consumer advocate agency and want to estimate the population mean cost of replacing a car’s transmission. As part of your study, you randomly select 50 replacement costs and find the sample mean to be $2,650.00. The sample standard deviation is $425.00. However, you also know from previous work that the population standard deviation, σ_x = $400.00.

Find the number of transmission replacement costs (in total) needed to be included in a sample to be 95% sure that the point estimate X-bar, will be within an Error of $100.00 (E = $100.00) from the true population mean cost.

	a.	62
	b.	44
	c.	8
	d.	784

Answer 1