What is the standard deviation of the following set of data

Two friends are reading books. jimmy reads a book with 21,356 words. his friend bob reads a book with one-and-a-half times as many words. which expression represents the number of words bob reads?

Over the course of the school year, you keep track of how much snow falls on a given day and whether it was a snow day. your data indicates that of twenty-one days with less than three inches of snow, five were snow days, while of the eight days with more than three inches of snow, six were snow days. if all you know about a day is that it is snowing, what is the probability that it will be a snow day?

The coordinates r(1, -3), s(3, -1) t(5, -7) form what type of polygon? a right triangle an acute triangle an equilateral triangle an obtuse triangle