1. Test the claim about the population mean, ?, at the level ofsignificance, ?. Assume the population is normally distributed.
Claim: ? ? 47, ? = 0.01, ? = 4.3 Sample statistics: ?? = 48.8, ?= 40
A. Fail to reject ?0. There is enough evidence at the 1%significance level to support claim.
B. Not enough information to decide.
C. Reject ?0. There is enough evidence at the 1% significancelevel to reject the claim.
2.
Use the following information to answer questions 28, 29, and30. The heights in inches of 10 US adult males are listedbelow.
70 72 71 70 69 73 69 68 70 71
a) Determine the range.
b) Determine the standard deviation.
c) Determine the variance.
3. The weights in pounds of 30 preschool children are listedbelow. Find the five number summary of the data set.
25 25 26 26.5 27 27 27.5 28 28 28.5
29 29 30 30 30.5 31 31 32 32.5 32.5
33 33 34 34.5 35 35 37 37 38 38
4. A manufacturer receives an order for light bulbs. The orderrequires that the bulbs have a mean life span of 850hours. Themanufacturer selects a random sample of 25 light bulbs and findsthey have a mean life span of 845 hours with a standard deviationof 15 hours. Assume the data are normally distributed. Using a 95%confidence level, test to determine if the manufacturer is makingacceptable light bulbs and include an explanation of yourdecision.
5. A manufacturer of golf equipment wishes to estimate thenumber of left-handed golfers. How large of a sample is needed inorder to be 95% confident that the sample proportion will notdiffer from the true proportion by more than 4%.
6.
A local group claims that the police issue at least 60 speedingtickets a day in their area. To prove their point, they randomlyselect one month. Their research yields the number of ticketsissued for each day. The data are listed below. Assume thepopulation standard deviation is 12.2 tickets. At ? = 0.01, testthe group’s claim. Make sure to state your conclusion regarding theclaim with your reasoning.
70 48 41 68 69 55 70 57 60 83 32 60 72 58 88 48
59 60 56 65 66 60 68 42 57 59 49 70 75 63 44
7. A local politician, running for reelection, claims that themean prison time for car thieves is less than the required 4 years.A sample of 80 convicted car thieves was randomly selected, and themean length of prison time was found to be 3.5 years. Assume thepopulation standard deviation is 1.25 years. At ? = 0.05, test thepolitician’s claim. Make sure to state your conclusion regardingthe claim with your reasoning.
