1. A consumer agency claims that the monthly sale of all the supermarkets in Metro Manila has increased 12% during the mega sales month last year. A random sample of 50 of such supermarkets taken recently recorded a 13.5% growth in monthly sales during the mega sales month. Assumed that the monthly sales of all the supermarkets in metro Manila have a normal distribution. At 0.01 significance level, are there any changes in the monthly sales of all the supermarkets in Metro Manila during the mega sales month? Solution: Step 1: Formulate the null and alternative hypotheses Ho: Ha: Step 2: Type of test: Step 3: Compute the test value: Draw the rejection region: Step 4: Decision