1.A simple random sample of 50 accounts is taken from an account receivables portfolio of XYZ Ltd and the average account balance is $650. The population standard deviation is known to be $70.

(6 marks)

a.Test the hypothesis that the population mean account balance is greater than $620 using critical value approach and a 0.05 level of significance.

b.Test the hypothesis that the population mean account balance is less than $800 using the critical value approach and a 0.05 level of significance.

c.Test the hypothesis that the population mean account balance is different from $750. using critical value approach and a 0.05 level of significance.