Stats Starts Here 15 min

 Statistics (the discipline) is the science of collecting, analyzing, presenting and interpreting the data. It is a way of reasoning, a collection of tools and methods, designed to help us understand the world.  Statistics (plural) are particular calculations made from data.  Data are values with a context.

 Do those high center brake lights, required on all cars sold in U.S since 1986, really reduce rear-end collisions?  Randomized comparative experiments with fleets of rental and business cars, done before the lights were required, show that the third brake light reduced rear-end collisions by as much as 50%.  Alas, requiring the third light in all cars led to only 5% drop. Why?

 Descriptive Statistics refers to methods for summarizing and organizing the information in a data set.  Inferential Statistics consists of methods for estimating and drawing conclusions about population characteristics based on the information contained in a subset (sample) of that population.

State whether the following situations illustrate the use of descriptive or inferential statistics. 1. The average for the first test in this class is 75% with the highest score being 99%. 2. In a survey of 1000 citizens in Seattle, Washington, metropolitan area, 570 said they would pay higher prices in order to reduce greenhouse emissions. City planners conclude that 57% of all Seattle citizens would do so. 3. GCC enrollments this semester is up 14% compared to last fall.

 Statistics is about variation.  Statistics gives us a way to work with the variability in the world around us.  Statistics helps us understand the real, imperfect world in which we live.  All measurements are imperfect, since there is variation that we cannot see.  Probability must be involved to predict chances or errors associated with the conclusions.

 Statistics course is not really a math course! (like accounting)  Statistics can be fun! Learning to think clearly with data will open your eyes to seeing the world more clearly…  Example: ASU president Michael Crow proposed tuition increase by showing the fact that tuition cost at ASU is still in the lower one-third of senior research university tuitions.

 ASU president Michael Crow once claimed that “Of students enrolled in the Maricopa County Community College District who are eligible to move into a state university, only 15 percent ever receive a degree.” Actual statistics: “39% of the students are attending college with a goal of transferring to a university, a decrease of about 1%, while 41% have a goal of obtaining training so they can enter the workforce, an increase of 2%. Another 16% said they were attending college for personal enrichment.”