The number N of residential homes that a fire company can serve depends on the distance r (in city blocks) that a fire engine can cover in a specified (fixed) period of time. If we assume that N is proportional to the area of a circle R blocks from the firehouse, then N = C R2 , whereC is a constant, = 3.1416 ..., and R, a random variable, is the number of blocks that a fire engine can move in the specified time interval. For a particular fire company, C = 8, the probability distribution for R is as shown in the accompanying table, and p(r) = 0 forr 20 and r 27. r 21 22 23 24 25 26 p(r) .05 .20 .30 .25 .15 .05 Find the expected value of N, the number of homes that the fire department can serve.

Exam 1: Study Guide Lecture 2: Rafia Chaudhary Statistics is the art and science of learning from data Individuals (also known as subjects, instances, and observations) are the things we get our data from. Who/what do we get our data from o These are often people, animals, or other living things but don’t need to be Variable: any characteristic or piece of information about an individual o Is an answer to a question, like how tall are you What’s your name etc. Ex: you are working for a drug company and you are developing a new drug to treat the common cold o Individuals: humans o Variables: measure of patient’s symptoms, time it takes f