1. Discrete Math Section 17.5 Recognized types of sampling procedures and estimate population characteristics based on samples The purpose of sampling is to study a small subset to learn the characteristics of the entire population. Terminology Population – the entire set of objects Sample- a subset of the population Sampling- selecting a sample

2. Types of sampling 1.Probability sampling – based on random procedure a. Simple random – each individual has an equal chance to be selected. b. Stratified random - population is broken down into groups in which the percent of the entire population is known. 2.Nonprobability sampling a. Convenience- individuals are chosen because of their ease. b. Judgment- experts choose a representative sample c. Questionaire- question are answered by volunteers.

3. problem A sample of 6 typed pages of a 50 page report contain the following errors. Estimate the total number of errors in the report. Page 1 2 3 4 5 6 Errors 1 0 2 1 3 3

4. problem A school has 960 students and 40 teacher. The school newspaper interviews 60 students and 12 teachers to see whether they favor changing a school policy. The results are given below. Estimate the percent of the school population favoring the change. StratumPopulation Size Sample Size Number favoring change Students Teachers 960 40 60 12 32 4 Total 1000 72 36

5. assignment Page 673 Problems 1-9, 11,12