1) The normally distributed AAA battery life is stated to be 350 days when used in a clock radio. The Big Charge Battery Company has recently modified the AAA batteries so as to extent their life. The owner of the company wanted to know if the improved batteries really did last significantly longer. A sample of 100 of the improved batteries was tested. It was discovered that the mean life was 362 days and the sample standard deviation was 10 days. The research department decided to conduct the test at the 0.05 level of significance whether the modification actually increased the life of the AAA battery. What was their decision rule?
A. Do not reject the null hypothesis if the z test statistics is 1.96 or greater.
B. Reject the null hypothesis if computed z is less than 1.96.
C. Reject the null hypothesis if computed z is 1.96 or greater.
D. Do not reject the null hypothesis if computed z is 1.65 or greater.
2) An independent consumer testing lab preformed a statistical test on 25 type-C alkaline batteries and calculated the mean life for a particular use before they failed was 22.5 hours. The distribution of the lives approximated a normal distribution. The standard deviation of the distribution was 1.1 hours. Information on the package states that the batteries should last 24 hours.
The test question was if this difference between the test statistics and the stated life of the battery was significant? The .05 significant level was selected for the test. Which is the correct statement?
A. The difference was significant; the batteries do not meet the stated length of time.
B. The difference was not significant.
C. The difference indicates that the batteries are not good.
D. The difference cannot be evaluated with this small of a sample.
3) The statement that determines if the null hypothesis is rejected or not is called the
A. test statistic
B. alternate hypothesis
C. critical value
D. decision rule
4) In classical hypothesis testing, the test statistic is to the critical value what the ________________.
A. critical value is to alpha
B. test statistic is to the p-value
C. level of significance is to the test statistic
D. p-value is to alpha
5) The Roman Senate has become concerned about the loyalty of the army in Gaul commanded by Julius Caesar. They claim that, of the 80,000 men in the army, at least 28,000 are foreign barbarians. Caesar believes there are fewer barbarians, so the Senate should not worry. He polls one legion of 1,000 men and finds that 340 of them are barbarians. What is the test statistic for this hypothesis test?
6) K & S Construction, located in Phoenix, Arizona, is working on its business plan for the upcoming year. They did a study to determine if they should focus on building condominiums or individual houses. A building study, which had been conducted by the state, indicated that 60 percent of those families looking to buy a home in Arizona desired to buy a condominium. K & S Construction wanted to know if this figure applied to Phoenix. They collected a sample of 500 individuals that had expressed plans to buy a new home. The z-distribution was selected for this proportion test. The null hypothesis is p = 0.60 and the alternate is p ≠ 0.60. The significant level selected was .05. From the sample of 500, it was determined that 290 wanted to buy a condominium. What decision should be made regarding the null hypothesis?
A. Reject it
B. Cannot accept nor reject it based on the information given
C. The test level of .05 is not acceptable
D. Fail to reject it
7) A machine is set to fill the small size packages of Good and Better candies are packaged with 60 pieces of candies in each bag. Sampling results revealed: 3 bags of 61, 2 bags of 59, 1 bag of 58, and 2 bags of 62. How many degrees of freedom are there?
8) You are conducting a two-tailed test of means but your software package only calculates a one-tailed p-value equal to 0.13. The actual p-value for your test is
C. need a table to calculate this value.
9) If the paired differences are normal in a test of mean differences, then the distribution used for testing is the
B. Student t distribution
C. F distribution
D. normal distribution
10) One hundred women were polled and 60 reported successfully communicating an automobile problem to an auto repairman. A sample of 150 men had 95 reporting the same success. The value of the test statistic for a test of the equality of proportions is
11) Newton’s, a tire manufacturer, wanted to set a mileage guarantee on its new Road Warrior 60 tire. A sample test of 500 tires revealed that the tire’s mileage is normally distributed with a mean of 50,000 miles and a standard deviation of 1,750 miles. The warranty on the tires is presently set at 47,500 miles. The z-test statistic result was 1.43. The manufacturer wanted to determine if the tires were exceeding the guarantee. At the .05 significant level, it was concluded that the tires are exceeding the manufacturer’s guarantee.
A. This was the correct decision.
B. A decision cannot be made.
C. The evidence does not support this decision.
D. The decision needs to be delay until more data is collected.
12) In a test for the equality of two variances (two-tailed), when the populations are normal, a 5% level of significance was used. Sample sizes were n1 = 13 and n2 = 10. The upper critical value for the test is
A. =FINV(0.025, 12, 9).
B. =FINV(0.025, 13, 10).
C. =FINV(1-0.025, 13, 10).
D. =FINV(0.05, 12, 9).
13) Accounting procedures allow a business to evaluate their inventory at LIFO (Last In First Out) or FIFO (First In First Out). A manufacturer evaluated its finished goods inventory (in $ thousands) for five products both ways. Based on the following results, is LIFO more effective in keeping the value of his inventory lower?
Product FIFO (F) LIFO (L)
1 225 221
2 119 100
3 100 113
4 212 200
5 248 245
The 5% level of significance was selected for the t value. This example is what type of test?
A. Two sample test of means.
B. Paired t-test.
C. Test of proportions.
D. One sample test of means.
14) When is it appropriate to use the paired difference t-test?
A. Any two samples are compared
B. Two dependent samples are compared
C. Four samples are compared at once
D. Two independent samples are compared
15) Indy H2O is a water bottling company. They are looking at two different bottling manufacturers’ equipment for the purpose of replacing some old equipment. The net weights of a sample of bottles filled by a machine manufactured by WTR, and the net weights of a sample filled by a similar machine manufactured by Target are (in grams):
WTR: 8, 9, 7, 8, 9, and 10
Target: 8, 10, 7, 11, 9, 12, 8, and 9
Testing the claim at the 0.05 level that the mean weight of the bottles filled by the Target machine is greater than the mean weight of the bottles filled by the WTR machine, what is the critical value?
16) You are conducting a two-tailed test of means, but your software package only calculates a one-tailed p-value equal to 0.13. The actual p-value for your test is
B. You need a table to calculate this value.
17) When testing for differences between two means, the Behrens-Fisher problem arises when the sample populations are
A. are normal with unequal variances.
B. are non-normal and have unequal variances.
C. normal with equal variances.
D. are non-normal and have equal variances.
18) If the paired differences are normal in a test of mean differences, the distribution used for testing is the
B. f distribution.
C. normal distribution.
D. student t distribution.
19) A trolley system is being planned for the downtown area of Cincinnati, Ohio. To be able to proceed with this project, planners have indicated that at least 20% of the residents of the areas that would be covered need to support the idea. To determine the feelings of these city residents, a sample of 300 residents was taken. Seventeen percent of the sample responded that they would ride the trolley. Is this enough evidence for the project to proceed? Use the .05 level of significant.
A. A t-test would be the best choice for the test.
B. A decision cannot be made either yes or no.
C. There is enough evidence; move forward with the project.
D. There is not enough evidence to support the moving forward with the project.
20) Watson’s TV claims that their televisions have the best performance record on the market. They advertise that after 3 years only 10% of their sold televisions have had any type of repairs. The president of the company wanted to confirm that this statement was correct. To do this, a sample of 60 sets was taken of sets that had been sold and were at least 3 years old. Twelve percent of these television sets had been in for repair. The null hypothesis is that there is no difference between the stated percent and the sample data. At the .05 significant level, what can we conclude about the null hypothesis?
A. The data fails to reject the null hypothesis.
B. The difference is too close to be able to decide.
C. The null hypothesis is rejected and the difference is significant.
D. The sample is too small to be able to decide.
21) New college business graduates are finding it difficult to get a job. A business journal has reported that only one in five graduates is able to find a job within 6 months of their graduation. A report by the University of Phoenix indicated that out of a survey of 300 recent business graduates, 75 had jobs. You are a business major at the University of Phoenix and have a concern about getting a job. Based on this data, will a graduate of the University of Phoenix have a better chance of getting a job in the first 6 months after graduation? Use the .05 significant level for the test.
A. Cannot be predicted based on this data.
B. The business journal information is incorrect.
C. No, there is not a significant difference.
D. Yes, there is a significant difference.
22) Blake’s Mortgage Company utilizes four different appraisers for the purpose of determining the value of a house. There is a concern by the company’s owner that the appraisers are not providing the same estimates. She wants to determine if there is a difference between the four appraisers. Six houses were selected and each appraiser provided an appraisal for each of the six houses. What would be the best statistical test to use for the analysis of this data?
A. Kruskal-Wallis test
B. An ANOVA
C. A paired t-test
D. Chi square test
23) The F distribution is utilized with the ANOVA test. There are some basic assumptions associated with the distribution. Which of these assumptions is NOT valid?
A. It is a continuous distribution.
B. It is negatively skewed.
C. There is a family of distributions.
D. Its values cannot be negative.
24) Which is NOT a valid assumption for the utilization of the ANOVA test?
A. The populations have equal standard deviations.
B. The samples are independent.
C. The MSE/MST provides the test statistics for the F distribution.
D. The samples are from populations that follow the normal distribution.
25) Robinson, a large department store, wanted to example to look at which credit cards were being utilized for purchases. A sample of 18 credit card sales was taken and recorded. The amounts charged for each of three different credit cards, MasterCard, Visa, and Discover, were: six MasterCard sales, seven Visa sales, and five Discover sales. The store used an ANOVA to test if the mean sales for each credit card were equal. What are the degrees of freedom for the F statistic?