A local group claims that the police issue at least 60 speeding tickets a day in their area. To prove their point, they randomly select one month. Their research yields the number of tickets issued for each day. The data is listed below. Assume the population standard deviation is 12.2 tickets. At α = 0.01, test the group's claim.
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
Ho: x is greater than or equal to 60 (claim of the local group)
Ha: x is less than 60
Mean is 60.387097
Standard Deviation is 12.2 tickets
Z= 0.4/12.2/square root (31) = 0.1825
P(z<0.1825)= 0.5724
0.5724>0.01
The claim is correct.