If the problem below is given: Suppose that a garage samples 18 customers. They find the average time for there oil change is 4,284 miles. Find a 90% confidence interval of the true mean, if the...

If the problem below is given:

Suppose that a garage samples 18 customers. They find the average time for there oil change is 4,284 miles. Find a 90% confidence interval of the true mean, if the population standard deviation is 1,132.

What is the lower bound of the confidence interval? (round to the correct integer)