Batteries In a group of 10 batteries, 3 are dead. You choose 2 batteries at random. a) Create a probability model for the number of good batteries you get. b) Whats the expected number of good ones you get? c) Whats the standard deviation?
Statistics 260 1/22/18 – 1/26/18 Chapter 2 Why do we have statistics - The census is taken every 10 years by law - Due to technology we can take estimates during years in which we can’t take the actual census - Pulling data from the population o We are able to discover true parameters o It takes a lot of time and money to count the entire population so we can take a sample instead o We use a sample to find statistics do estimate parameters. Costs less time and money - Two branches o Descriptive statistics Numerical summaries of graphical displays of data. Graphical Numerical DESCRIPING data