The number of vehicles on a highway link is counted on each of 40 randomly chosen...

The number of vehicles on a highway link is counted on each of 40 randomly chosen days. The mean number of vehicles is found to be 135, and the standard deviation is 90.

(a) Find a 90% confidence interval for the sample mean. (3)

(b) Find a 90% confidence interval for the mean, assuming it had been based upon a sample of 15 days, instead of a sample 40 days. (3)

Expert Solution

orchestra answered 2 years ago

1. The number of vehicles on a highway link is counted on each of 40 randomly...

1. The number of vehicles on a highway link is counted on each of 40 randomly chosen days. The mean number of vehicles is found to be 135, and the standard deviation is 90. (a) Find a 90% confidence interval for the sample mean. (b) Find a 90% confidence interval for the mean, assuming it had been based upon a sample of 15 days, instead of a sample 40 days. Thank you very much!

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