Determine the needed data, identify whether the given data is for Z-test or T-test, and

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A manufacturer of tires claim that their tire has a mean life of higher than 37,800 kms. A

random sample of 28 of these tires is tested and the sample mean is 32,000 kms. Assume that

the population standard deviation is 13,500 kms and the lives of the tires are approximately

normally distributed.

a. Needed data (4pts)

b. Z-test or T-test (1 pt)

c. Solution and answer (5pts)

2. The government claims that the monthly expenses of a family with four members is

11,800. A sample of 26 family's expenses has a mean of 12,500 and a standard deviation of

1,550.

a. Needed data (4pts)

b. Z-test or T-test (1 pt)

c. Solution and answer (5pts)

3. In the first semester of the school year, a random sample of 200 students got the mean of 81.72

with a population standard deviation of 15 in Statistics and Probability test. The population

mean is 79.83.

a. Needed data (4pts)

b. Z-test or T-test (1 pt)

C. Solution and answer (5pts)