The mean life span of a brand name tire is 50,000 miles. Assume that the life...

The mean life span of a brand name tire is 50,000 miles. Assume that the life spans of the tires are normally distributed, and the population standard deviation is 800 miles.
- a. If you select one tire, what is the probability that its life span is less than 48,500 miles?
- b. If you select 100 tires, what is the probability that their mean life span is more than 50,200miles?
- c. What is the distribution of the sample mean in part b?
The proportion of students at a college who have a GPA higher than 3.5 is 19%.
- a. You take repeated random samples of size 25 from that college and find the proportion of student who have a GPA higher than 3.5 for each sample. What is the mean and the standard error of the sampling distribution of the sample proportions?
- b. You take repeated random samples of size 50 from that college and find the proportion of student who have a GPA higher than 3.5 for each sample. What is the mean and the standard error of the sampling distribution of the sample proportions?
- c. Compare the results of parts a and b, and sketch the sampling distributions.

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orchestra answered 1 year ago

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