A company wants to estimate how long it will take to produce 100 units of a product based on production rates in the past. Which statistical method would be most effective? - use a confidence interval with the average of all production lines for all products as the mean - a regression with production as the independent variable - hypothesis testing with a null hypothesis that the production time is greater than or equal to the mean - hypothesis testing with a null hypothesis that the production time is less than or equal to the mean - use a confidence interval with the past average production time as the mean