Answered>Order 1893

  A simple random sample of 40 accounts is taken from an account receivables portfolio of ABC Ltd and the average account balance is $750. The population standard deviation ? is known to be $80. (6 points)

1. Test the hypothesis that the population mean account balance is greater than $680 using the p-value approach and a 0.05 level of significance.
2. Test the hypothesis that the population mean account balance is less than $820 using the critical value approach and a 0.05 level of significance.
3. Test the hypothesis that the population mean account balance is different from $800. using the p-value approach and a 0.05 level of significance.