Problem: An internet service provider sampled 540 customers and found that 75 of them experienced an interruption in high-speed service during the previous month.

Questions:

a) Find a point estimate for the population of all customers who experienced an interruption

b) Construct a 90% confidence interval for the proportion of all customers who experienced an interruption

c) The company's quality control manager claims that no more than 10% of its customers experienced an interruption during the previous month. Does the confidence interval contradict this claim? Explain.