A radio shop sells $,$on an average $200$ radios per day with a standard deviation of $50$ radios $.$ After an extensive advertising campaign, the management will compute the average sales for the next $25$ days to see weather an improvement has occurred. Assume that the daily sales of radios is normally distributed. Test the hypothesis at $5\%$ level of significance if X mean $=216.$ How large must X mean be in order that the null hypothesis is rejected at $5\%$ level of significance $(1\mathrm{.}645)$

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To test the hypothesis at a 5 level of significance we will use a onesample ztest Given Population m... View the full answer