1. If you reject the null hypothesis at a = .05, you would also reject at a = .10.

1. True
2. False

1. You are testing to determine if hiring a new employee has decreased the mean time to wait on customers. You have randomly selected 7 customers and do not know the standard deviation of waiting times. Which procedure is most appropriate?

1. t-test
2. z-test
3. some other fine procedure.

1. If we increase the level of confidence,

1. the sample size will increase.
2. the margin of error will increase.
3. the z-value will decrease.
4. something else will occur (like maybe Harry Potter putting a spell on you).

1. The sample size required to meet the normality requirement for the sample mean for the paired t-test is _____ than that required for a one-sample t-test.

1. smaller
2. larger
3. can not be determined

1. In a certain application, you have deemed a Type II error to be the most serious error. You would select a relatively _______ value of .

1. large
2. small
3. can not be determined

1. You are computing a 95% confidence interval for the mean basis weight for a type of fabric.If the standard deviation of basis weights is 2 g, find the sample size required to ensure a margin of error of .98 g.(3)

1. In #6, suppose you change the margin of error requirement to .5. The sample size required will (2)

1. increase.
2. decrease.
3. not be affected.

1. You are monitoring a process that produces fiber-optic cable. If the process is on-target, the mean diameter for the cable is 80 mils and the standard deviation of 2 mils. A random sample of 100 pieces of cable yields a mean diameter of 81.2 mils. Test to determine if the mean diameter differs from 80 mils. Use = .05.

a. State the hypotheses. (2)

1. The appropriate test is a _____ test. (2)

1. Compute the test statistic. (3)

d. The p-value is (small / large). (2)

1. The appropriate decision is to ___________________ the null hypothesis. (2)

1. State your conclusion. (2)

1. Here, a Type I error would be committed if we(2)

1. determine that the diameter differs from 80 mils when it does not.
2. determine that the diameter does not differ from 80 mils when it does.
3. determine that the mean diameter is 80 mils when it is not.
4. determine something entirely different from a-c.

For 10, refer to the Excel output.

1. One set of output is for a test to determine if the mean tensile strength of a fabric is less than 620 g/si. We do not know the standard deviation of tensile strengths.

1. The value of the test statistic is __________.(2)

1. The appropriate critical value is __________.(2)

1. The decision is to ________________ the null hypothesis. (2)

1. We would conclude that the mean tensile strength is less than 620 g/si. (True / False) (2)

1. You are estimating the proportion of students who want to take more online classes in summer if they are offered. In a random sample of fifty (50) students, twenty (or 40%) said that they would take more online classes if offered. Find a 99% confidence interval for the proportion of students who want to take more online classes in summer if they are offered.(4)

1. Refer to the Excel output. You are next asked to assess the production rates for Casey and Jason over the same week. Random samples of twenty-two (22) periods have been selected, and for each the number of units produced has been verified. (Refer to the appropriate output.) (2 ea.)

1. In testing for equality of the variances, the test statistic = ____________.

1. The p-value = __________.

1. The variances differ significantly. (True / False)

1. Appropriate output for testing if there is a difference in the mean number of units produced for the two operators is given.(True / False)

1. In testing for equality of the means, the test statistic = ____________.

1. The p-value = __________.

1. The means differ significantly. (True / False)

1. Based on the above, which operator (if either) has greater productivity? (Casey / Jason)

1. You are assessing the effectiveness of a new computer-assisted learning program for your employees. Specifically, you are wanting to determine if the program is superior to the current traditional program. If you have 100 employees available, discuss how you could set this up as 1) an independent sample procedure, and 2) as a paired procedure.In your discussion, consider the advantages and disadvantages of each. (8)

F-Test Two-Sample for Variances
	Casey	Jason
Mean	14.22727	11.40909
Variance	2.183983	2.062771
Observations	22	22
df	21	21
F	1.058762
P(F<=f) one-tail	0.448569
F Critical one-tail	2.084189
t-Test: Two-Sample Assuming Equal Variances
	Casey	Jason
Mean	14.22727	11.40909
Variance	2.183983	2.062771
Observations	22	22
Pooled Variance	2.123377
Hypothesized Mean Difference	0
df	42
t Stat	6.414338
P(T<=t) one-tail	5.03E-08
t Critical one-tail	1.681952
P(T<=t) two-tail	1.01E-07
t Critical two-tail	2.018082

t-Test and Estimate: Mean		Z-Test: Mean
		Strength			Weight
Mean		581.35		Mean	23.9546
Standard Deviation	65.5971		Standard Deviation	1.8224
Hypothesized Mean	620		Observations	36
df		19		Hypothesized Mean	24
t Stat		-2.635		SIGMA	1.5
P(T<=t) one-tail	0.0082		z Stat	-0.1817
t Critical one-tail	1.7291		P(Z<=z) one-tail	0.4279
P(T<=t) two-tail	0.0164		z Critical one-tail	1.6449
t Critical two-tail	2.093		P(Z<=z) two-tail	0.8558
				z Critical two-tail	1.96
Standard Error	14.668
Bound		30.7005
LCL		550.6495
UCL		612.0505