1. Sampling

2. Definitions
Statistics = the study of procedures for collecting, describing, and drawing conclusions from information.

3. Definitions
Population = the entire collection of individuals about which information is sought
Sample = a subset of a population, containing the individuals that are actually observed

4. Definitions
Simple Random Sample of Size n = A sample chosen by a method in which each collection of n population items is equally likely to make up the sample, just as in a lottery

5. Random Numbers
Seed = A number that the calculator uses to get the random number generator started.
3-> rand
Then
randInt(1,20,4)
This chooses four integers between 1 and 20
Note: Calc Functions are located “Math” -> “Prb”

6. Definitions
Sample of Convenience = A sample that is not drawn by a well-defined random method.
Note: The sample of convenience may be acceptable if the sample represents the population.

7. Other Sampling Methods
Stratified Sampling = population divided into homogenous (similar) groups called stratums then a simple random sample is drawn from each stratum
Example: Democrat and Republican

8. Other Sampling Methods
Systematic Sampling = Population items are ordered and every kth individual is selected. Usually the first one chose for the sample is done randomly.
Voluntary Response Sampling = Sample is done by the individuals volunteering (such as calling into a radio station)

9. 1. Identify the type of sampling used
An instructor walks into a classroom and asks his students whether they are for or against making marijuana legal.

10. 2. Identify the type of sampling used
The instructor randomly picks the number 7 and randomly picks the number 5. He then takes a sample of students coming out of the library starting with the 7th student and every 5th one after that.

11. 3. Identify the type of sampling used
Administration splits the students at a college into two groups (Men and Women) and randomly picks from within each group.

12. Definitions statistic = a number that describes a sample
parameter = a number that describes a population

13. 4. Determine whether the underlined value is a parameter or a statistic
The average grade for a class of 25 students in Elementary Statistics was 83.2%

14. 5. Determine whether the underlined value is a parameter or a statistic
In a survey of high school students, 74% of respondents indicated that they had cheated at least once on an exam in the past year.
Source:

15. 6. Determine whether the underlined value is a parameter or a statistic
In a survey, it was found that 10% of married people have had extramarital affairs in the last year.
Source:

16. 7. Determine whether the underlined value is a parameter or a statistic
In a particular Elementary Statistics class only 50% of guys wash their hands after using the bathroom.