1. The Four Techniques for Gathering Data
September 2, 2011

2. The Four Techniques OBSERVATIONAL STUDY SAMPLE SURVEY CENSUS
EXPERIMENT

3. You observe, but do not interact with your subject(s).
Sometimes you know what it is you are looking for; other times, you may not know, so you note everything you see.
OBSERVATIONAL STUDY

4. SAMPLE SURVEY
These are considered an observational study, as the person conducting the study does not do anything which can influence the subject.
Sample surveys question only a small number of the population, and then generalize the results to include the entire population.

5. The CPS is the most important government sample survey in the U. S
The CPS is the most important government sample survey in the U.S. Many variables concern the employment status of everyone over the age of 16. It also records many other economic and social variables. The population is more than 100 million households; the sample size is 50,000 households per month.

6. CENSUS
The US Census is a survey that is conducted every 10 years and attempts to include the entire population.
It is used to determine equality in such things as political boundaries, number of schools and stores in areas, etc.

7. The Questions in the 2010 Census
How many people were living or staying in this house, apartment, or mobile home on April 1, 2010?
Were there any additional people staying here April 1, 2010 that you did not include in Question 1?
Is this house, apartment, or mobile home: owned with mortgage, owned without mortgage, rented, occupied without rent?
What is your telephone number?
Please provide information for each person living here. Start with a person here who owns or rents this house, apartment, or mobile home. If the owner or renter lives somewhere else, start with any adult living here. This will be Person 1.
What is Person 1's name?
What is Person 1's sex?
What is Person 1's age and Date of Birth?
Is Person 1 of Hispanic, Latino or Spanish origin?
What is Person 1's race?
Does Person 1 sometimes live or stay somewhere else?

8. CENSUS

9. But what about a “census”
Upper case Census usually refers to the US Census.
Lower case census refers to any sample survey which uses the entire population of a group (i.e., all students at Irvington, all residents of Fremont).
A census can also be the size of a class, however, the larger the population, the more accurate the results you will receive.

10. EXPERIMENTS
In an experiment, two or more groups of subjects receive different “treatments” and the results are compared.
This is different from an observational study as you are interacting with your subjects.

11. EXPERIMENTS Treatment Group Placebo Group
A treatment can be a new type of medication or a new product to be tested before being made available to the public. You will be trying to prove its effectiveness compared to a different treatment or a placebo.
A placebo is a dummy treatment, which can take the form of a sugar pill (something with no medicinal value). It can also be the old version or formula of the product you are working with.

12. EXPERIMENTS
The experiment continues until it has been determined there has been a significant response to the treatment (either positive or negative). Or there has been no reaction at all.
Neither the experimenter, nor the subjects, knows who has received which treatment.
Why?

13. Group Activity #2 Put away your notes.
On a sheet of paper, with the assistance of all members of the group, list at least 4 words or phrases which indicate you are speaking about each of the 4 data gathering methods.
The name of the method does not count as one of the answers.