The waiting times for the treatment of a specialized steel are assumed to be normally distributed, with unknown mean and standard deviation. As an enterprising co-op student, you perform 25 tests. Find an interval bracketing the probability that you will observe a standard deviation in waiting time exceeding 5 minutes when the true standard deviation is (a) 4.3 minutes or (b) 6.0 minutes.

Given: x + y = 6. if xe (-15, -6, -1), then which of the following sets of ordered pairs are solutions? © {(-15, -21), (-6, -12), (-1, -7)} [(-15, 21), (-6, , 7)} {(-15, 21), (-6, 12), (-1, -7)}

The sales totals at macy's food store have increased exponentially over the months. which of these best shows the sales in the first three months?

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?