SOC 3811 Basic Social Statistics

1 / 16

# SOC 3811 Basic Social Statistics - PowerPoint PPT Presentation

SOC 3811 Basic Social Statistics. Announcements. Assignment 2 Revisions (interpretation of measures of central tendency and dispersion) — due next lab. No midterm exam revision policy. . Class overview. Concept review - descriptive v.s. influential statistics

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.

## PowerPoint Slideshow about 'SOC 3811 Basic Social Statistics' - Mia_John

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
SOC 3811

Basic Social Statistics

Announcements
• Assignment 2 Revisions (interpretation of measures of central tendency and dispersion)—due next lab.
• No midterm exam revision policy.
Class overview
• Concept review

- descriptive v.s. influential statistics

- null and alternative hypotheses

- test statistics (sampling distributions)

- type 1 and type 2 errors

• M & M activities
Inferential Statistics
• Descriptive statistics:

to describe or summarize the data of a sample

• Inferential statistics:

to make generalizations about a population using a sample

eg: GSS —> the American Population

(estimators parameters)

Necessary conditions for inference
• With a large enough N.
• It is representative.
• It’s a random sample.

(We take it at lots of different times and places.)

Usually if the sample is truly random, it will also be representative.

How to make inferences?
• Need to do hypothesis testing!
• Steps:

2. random sampling

3. make statistical tests

4. draw the conclusion (reject or accept your hypothesis. )

Test the null hypothesis
• Create hypotheses:

the null hypothesis and alternative hypothesis should be mutually exclusive.

• Get the “estimates” from random samples.
• Test if the estimate is a close estimate? (Hint: if the null hypothesis is true, what are the expected behaviors of some test statistics? Compare if these test statistics behave close enough. )
Sampling distributions
• Central Limit Theorem
Test statistics
• z, t, χsquare, F.
• specify α: we can set an acceptable confidence interval (/ probability of type 1 error, usually it’s .05)
• Compare the value of the statistic with the expected test statistic.
M&M Activity
• Don’t eat your candies before you count them!!
Hypothesis Test: Steps
• State research hypothesis
• State null hypothesis
• Choose a probability of type 1 error. (This tells you how sure you want to be, 90%, 95%, 99%, etc.)
• Run an analysis in SPSS. (Determine mean and s.d. and significance level.)
• Compare the results to the predetermined values in steps 2 & 3.
• Decide whether you will accept or reject the null hypothesis.
Hypotheses?
• H0: p = .24
• Ha: p ≠ .24
Conclusion?
• for α=.05 (95% confidence level), Z=1.96 (Table D.2 in the textbook)
• Our conclusion?