3 . ( 7 points ) A sample of 49 sales receipts from Apple store has the sample mean of $450 and population standard deviation of $70 . Use these values to test whether or not the mean is sales at the Apple store are different from $500 . ( a ) ( 2 pts ) Find 95% Confidence Interval for a mean . ( b ) ( 5 pts ) Hypothesis Testing with significance level a = 0.05 Step 1 . State the null and alternative hypotheses . Step 2 . State Decision Rule for both p - value and critical value methods 0 Decision Rule for p - value method ` Decision Rule for Critical Value Method Step 3 . Find Test Statistic . Step 4 . Conclusion i . By p - value method li . By critical value method