Alocal supermarket organised two weeks of promotions to boost sales. the average dailly salles before the carmpaign is $10 000, which becomes $11 000 during the promotion (average over 2 weeks). which analysis below is not useful for evaluating whether the increase in sales is statistically significant?

1. check the distribution of sales data.
2. inspect for possible outliers in sales data.
3. calculate precision of the prediction
4. monitor sales for longer period of time.

1- is the product of two rational numbers irrational or rational? first, make a hypothesis by multiplying two rational numbers. then, use variables such as x=a/b and y=c/d and the closure property of integers to prove your hypothesis. 2- what do you think the product of a nonzero rational number and an irrational number is? is it rational or irrational? make use of variables, the closure property of integers, and possibly a proof by contradiction to prove your hypothesis. 3- why do we have to specify that the rational number must be nonzero when we determine what the product of a nonzero rational number and an irrational number is? if the rational number were 0, would it give us the same result we found in part b?