Statistics Unit 1 Lesson 1 An overview of Statistics

A good question…  What is Statistics, and why should I study it???  “Men who eat just two servings of tomatoes a week in raw, sauce, or pizza-from have a 34% less risk of developing prostate cancer.”  “More than three fourths of all college seniors in the United States complete at least one internship by graduation and 55% participate in two or more.”

 Data: Information from observation, counts, measuring, or responses  History of Statistics  Statistics: Science of collecting, organizing, analyzing, interpreting data to make decisions

Data Sets  Population: Collection of all outcomes, responses, measurements, counts  Why would this be difficult?  Sample: Only part of population (subset)

 Example: In a recent survey, 500 high school seniors were asked if they watch YouTube videos at least 3 times a week. Of the 500 seniors, 275 said yes.  Population:  Sample:

 Parameter: numerical description of population  Example: Population—Ms. Smith’s Stats students Parameter—2 out of 3 like pop music  Statistic: numerical description of sample  Example: Sample—every other person who walked in the lunchroom Statistic—65% said they like chicken tenders the best

Teamwork!! Decide if the value describes a population parameter or sample statistic. 1. A recent survey of a sample of MBAs reported that the average starting salary for an MBA is less than $65, Starting salaries for the 667 MBA graduates from the University of Chicago Graduate School of Business increased 8.5% from the previous year. 3. In a random check of a sample of retail stores, the FDA found that 34% of the stores were not storing fish at the proper temperature.

Branches of Statistics  Descriptive statistics: organizing, summarizing, and displaying data  Inferential statistics: use a sample to draw conclusions about a population (basic tool = probability)

Example  A large sample of men, aged 48, was studied for 18 years. For unmarried men, approximately 70% were alive at age 65. For married men, 90% were alive at age 65. Parts from Descriptive branch: Conclusion from Inferential branch:

 Homework: #2-36 even