Question #1

A random sample of 100 UAlbany graduates had an average hourly income of $50 with a standard deviation of $15.

Find the margin of error for the 90% confidence interval for the mean hourly wage of UAlbany grads.

	a.	2.624
	b.	1.312
	c.	1.64
	d.	1.968
	e.	2.46

Question #2

Suppose that you own a coffee shop. You want to estimate the population mean of the daily sales. A sample of past 5 days of sales data provided the following information:

Day	1	2	3	4	5
Coffees sold (in cups)	94	100	85	89	102

You are going to use the sample average as a point estimator for the population mean. You also want to measure the accuracy of your estimator, and use the standard error as the measure of the accuracy.

What is the standard error of your point estimator? When you calculate a variance or a standard deviation, use the sample version formula.

	a.	Square-root of 10.8
	b.	Square-root of 7.3
	c.	Square-root of 10.3
	d.	Square-root of 6.3
	e.	Square-root of 8.8