An accountant believes that a company’s cash flow problems are due to outstanding accounts receivable. She claims that 70% of the current accounts receivable is over 3 months old. A sample of 120 accounts receivable revealed 78 over 3 months old. Verify that the accountant's claim cannot be rejected at the at the 5% level of significance. Estimate the size of sample required to provide evidence, at significance level 0.05 and with power 0.9, of a reduction in the proportion (rom 70% to 60%)