Question 1 20 pts One reason for using a t distribution instead of the standard Normal curve to find critical values when calculating a level C confidence interval for a population mean that O z can only be used for large samples O z requires that you know the population standard deviation, o O z requires that you can regard your data as an SRS from the population. O the standard Normal table doesn't include confidence levels at the bottom O a z critical value will lead to a wider interval than a t critical value