When testing for current in a cable with eleven color-coded wires, the author used a meter to test four wires at a time. How many different tests are required for every possible pairing of four wires? The number of tests required is nothing.

Find the given elements if matrix d:

Monthly water bills for a city have a mean of $108.43 and a standard deviation of $32.09. find the probability that a randomly selected bill will have an amount greater than $155, which the city believes might indicate that someone is wasting water. would a bill that size be considered unusual?

I'm confused on this could anyone me and show me what i need to do to solve it.