The proportion of customers who are completely satisfied in a recent satisfaction survey of 400 customers at XYC Inc. is found to be 0.24. (6 points)

1. Test the hypothesis that the population proportion of customers who are completely satisfied is greater than 0.21 using the critical value approach and a 0.05 level of significance.
2. Test the hypothesis that the population proportion of customers who are completely satisfied is less than 0.28 using the p-value approach and a 0.05 level of significance.
3. Test the hypothesis that the population proportion of customers who are completely satisfied is different from 0.22 using the p-value approach and a 0.05 level of significance.