What do we study in the field of statistics? Example Suppose we are interested in the average number of calories consumed per day by undergraduate college students in the United States. We select 2500 undergraduates from across the country and collect this information.

What is the population? What is the sample? What is the variable? What is the data? Who are the individuals? What is the parameter? What is the statistic? The process of using 2500 undergraduate students to estimate all students in the U.S. falls under which branch of statistics? Is there any error involved in this process?

Suppose that instead of collecting data from the 2500 undergraduates selected you collected data from all undergraduates in the U.S. What would this be called? Collecting data from all undergraduates in the U.S. and summarizing that information falls under what branch of statistics? Is there any error involved in this process? Would it be realistic to collect data from all undergraduates in the U.S.?

Example Identify the type of each of the following studies: Suppose that we send out a survey to 1000 individuals asking about their consumption of fast food. An example item would be ‘How many times per week do you typically eat fast food?’ On Mythbusters they once tested to see if it was possible to kill someone by dropping a penny from the highest of heights.

Suppose that a study is designed to compare teaching methods. Specifically, we want to see if students learn introductory statistics better through an activities based approach or the more traditional lecture approach. Students will be assigned to one of the teaching methods and the result will be measured based on the final exam. Who are the subjects in the above study? What is the treatment in the above study? How many treatment groups are in the above study?

Example Suppose that we conduct a study looking at how diet and exercise effect a persons cholesterol level. For the diet variable we will have three types: atkins diet, south beach diet, and weight watchers diet. For the exercise variable we will also have three categories: walking, jogging, and biking. How many treatment combinations are there in this experiment? Create a treatment diagram to identify all treatment combinations.

Identify the data type for each of the following variables. If the variable is quantitative then identify it as discrete or continuous. The number of hotdogs sold at a Legend’s game Religious preference Student id number A persons weight Number of students in a class Temperature outside in Fahrenheit

Identify the level of measurement for each of the following variables. Year of high school graduation Rank of students in a graduating class The number of hotdogs sold at a Legend’s game Religious preference Student id number A persons weight Number of students in a class