Question

A coffee machine dispenses coffee into paper cups. You’re supposed to get 10 ounces of coffee, but the amount varies slightly from cup to cup. Here are the amounts measured in a random sample of 20 cups. Is there evidence that the machine is shortchanging customers? (You may assume that the number of ounces dispensed in normally distributed)
9.9 , 9.7 ,10.0 ,10.1 , 9.9 , 9.6 , 9.8 , 9.8 , 10.0 , 9.5 ,10.1 , 9.9 , 9.6 , 10.2 , 9.8 , 10.0 , 9.9 , 9.5 , 9.9 , 9.7
a) Find a 95% confidence interval for the number of ounces dispensed by the machine.

b) Write a sentence giving your results in the context of the problem.

c) What does 95% confidence mean in this problem?

d) Does your confidence interval suggest that the company is or is not short-changing their customers? Explain

Answer 1