1. The Process of a Statistical Study
Copyright © 2008 by Hawkes Learning Systems/Quant Systems, Inc.
All rights reserved.
HAWKES LEARNING SYSTEMS
math courseware specialists
Section 1.3
The Process of a Statistical Study

2. Defines Population/Variables
HAWKES LEARNING SYSTEMS
math courseware specialists
Introduction to Statistics
1.3 Process of a Statistical Study
Question
Defines Population/Variables
Estimate Parameter
Calculate Statistic
Collect Data

3. Observational Study – researcher observes data that already exists.
HAWKES LEARNING SYSTEMS
math courseware specialists
Introduction to Statistics
1.3 Process of a Statistical Study
Types of Studies:
Observational Study – researcher observes data that already exists.
Experiment – researcher seeks to create data to identify cause and effect relationships.

4. HAWKES LEARNING SYSTEMS
math courseware specialists
Introduction to Statistics
1.3 Process of a Statistical Study
Observational Study or Experimental Study?
A medical researcher wants to examine the effects of exercise on cardiovascular health.
Experimental
A recording company is interested in knowing the percentage of teenagers that download music off of the internet.
Observational
A chain of grocery stores wants to know how much the average family spends on produce each month.

5. Ask, “How will the data be gathered?” Very Important:
HAWKES LEARNING SYSTEMS
math courseware specialists
Introduction to Statistics
1.3 Process of a Statistical Study
Observational Studies:
Ask, “How will the data be gathered?”
Very Important:
It is essential that a representative sample is chosen out of the population.
A good sampling frame is the first step to choosing a representative sample. The sampling frame is a list of members of the population.

6. Census Random Sample Stratified Sample Cluster Sample
HAWKES LEARNING SYSTEMS
math courseware specialists
Introduction to Statistics
1.3 Process of a Statistical Study
Sampling Techniques:
Census
Random Sample
Stratified Sample
Cluster Sample
Systematic Sample
Convenience Sample

7. Every member of the population is included.
HAWKES LEARNING SYSTEMS
math courseware specialists
Introduction to Statistics
1.3 Process of a Statistical Study
Census:
Every member of the population is included.

8. Every member has an equal chance of being selected.
HAWKES LEARNING SYSTEMS
math courseware specialists
Introduction to Statistics
1.3 Process of a Statistical Study
Random Sample:
Every member has an equal chance of being selected.

9. The population is divided into subgroups called strata and the
HAWKES LEARNING SYSTEMS
math courseware specialists
Introduction to Statistics
1.3 Process of a Statistical Study
Stratified Sample:
The population is divided into subgroups called strata and the
same number of subject are chosen from each strata.

10. similar to the population and whole clusters are chosen at random.
HAWKES LEARNING SYSTEMS
math courseware specialists
Introduction to Statistics
1.3 Process of a Statistical Study
Cluster Sample:
The population is divided into subgroups, called clusters, that are
similar to the population and whole clusters are chosen at random.

11. Selecting every nth member of the population.
HAWKES LEARNING SYSTEMS
math courseware specialists
Introduction to Statistics
1.3 Process of a Statistical Study
Systematic Sample:
Selecting every nth member of the population.

12. The sample is convenient for the researcher to select.
HAWKES LEARNING SYSTEMS
math courseware specialists
Introduction to Statistics
1.3 Process of a Statistical Study
Convenience Sample:
The sample is convenient for the researcher to select.

13. HAWKES LEARNING SYSTEMS
math courseware specialists
Introduction to Statistics
1.3 Process of a Statistical Study
Identify the sampling method:
Chosen at random, 200 rural and 200 urban persons age 65 or older were asked about their health and experience with prescription drugs.
Stratified
For quality assurance, every 12th engine part is selected from an assembly line and tested for durability.
Systematic
A survey concerning the taste of a new soda flavor was performed at the local grocery store from 5:00 PM to 8:00 PM.
Convenience

14. HAWKES LEARNING SYSTEMS
math courseware specialists
Introduction to Statistics
1.3 Process of a Statistical Study
Identify the sampling method:
To determine how a particular political candidate was going to fare in an upcoming election, different counties in the state were randomly selected and every eligible voter in the randomly selected counties was surveyed.
Cluster
To determine who will win a $100,000 shopping spree at the local mall, the owner of the mall draws a name out of a box.
Random

15. Questions not Part of This Chapter
HAWKES LEARNING SYSTEMS
math courseware specialists
Introduction to Statistics
1.3 Process of a Statistical Study
Questions not Part of This Chapter
Don’t answer questions about:
Meta Analysis
Case Study
Single-Masked
Double-Masked

16. DATA WILL NOT BE CREATED !!!!!!!

17. MATH CLASSES ARE STRATAS, THE SAME NUMBER OF SUBJECTS ARE CHOSE FROM EACH STRATA.

18. EACH COUNTY IS A CLUSTER THAT IS SIMILAR TO THE POPULATION, AND THE WHOLE CLUSTERS (ALL THE MEMBERS) ARE CHOSEN AT RANDOM.

19. EVERY MEMBER OF THE POPULATION (ALL INSTRUCTORS) IS INCLUDED TO FIND THE AVERAGE SALARY.