1. Basic Statistics and Beyond Made Easy
We begin our journey into the world of statistics.
Jae Hak Jung, Ph. D, Senior Analyst, AIR

2. What is statistics?
Statistics- the science of colleting, organizing, analyzing and interpreting data.
Statistic: Data  Information
Let’s first define what exactly statistics is.

3. Data vs Information Data Information Raw Facts No Context
Just numbers and texts
Information
Data with Context
Processed data
Value-added to data
Summarized
Organized
Analyzed

4. Descriptive vs Inferential (1)
Descriptive statistics can be used to summarize and describe a single variable
Methods of organizing, summarizing, and presenting data in an informative way
Inferential
Hypothesis Testing
Correlation
Significant Testing
Prediction
The methods used to determine something about a population on the basis of a sample
When AIR provided the data to the client, We want to tell something about the data without giving them all of the data. Therefore, we provide the charts, tables, adding some mean and standard deviation. We call this descriptive statistics.
Some times, we also provided some deep analysis to help the client to make conclusion and make judgements. We called this inferential statistics.

5. Descriptive vs Inferential (2)
Descriptive Statistics
Frequencies & percentages
Means & standard deviations
Chart, Graph, Tabels.
Inferential Statistics
Correlation
T-tests
Chi-square
Logistic Regression

6. Descriptive Statistics

7. Mean The mean is the numerical average of the data set. Example:
The mean is found by adding all the values in the set, then dividing the sum by the number of values.
Example:
How many courses that FTIC student is taking for their first semester?
What is the average of credit hours earned for graduated?

8. Median
The middle number (just like the median strip that divides a highway down the middle; 50/50)
Used when data is not normally distributed
Often hear about the median price of housing

9. Mode
The most frequently occurring number (score, measurement, value, cost)
On a frequency distribution, it’s the highest point (like the á la mode on pie)

10. Mean, Median, Mode LSC-North Harris
What is the average of credit hours earned for Certificate_L1 Students graduated
What is the most meaningful statistics? N
371
Mean 53
Median 45
Mode 33

11. Measure of Variability
Variance
Population variance
Sample variance
Standard Deviation
Population standard deviation
Sample standard deviation
Range

12. Standard Deviation
Think of standard deviation as roughly as average distance of the observations from their mean. If all of the observations are same, then the standard deviation will be 0. Otherwise the standard deviation is positive.

15. Inferential Statistics
Who is doing a study that involves statistical analysis of data?
What type of (quantitative) data are you collecting?
Will there be enough data to achieve statistical significance? (adequate power vs. pilot) If pilot:
Descriptive statistics
Chart/graph

16. What type of statistical test do I want to do?
What type of data do you have?
What is your research questions?

17. Types of data Ratio: Continuous and having natural starting points
Annual Income, Credit hours, Weight
Interval: Continuous but no natural starting points
Most Personality measures, Likert Scale
Ordinal/Rank: Categories with some order
SES, Ranking
Categorical:
Gender, Ethnicity, Persist, Success

18. Continuous Data If comparing 2 groups (treatment/control)
t-test
If comparing > 2 groups
ANOVA (F-test)
If measuring association between 2 variables
Pearson r correlation
If trying to predict an outcome (crystal ball)
Regression or multiple regression

19. ANOVA
LSC-M Students’ Attempted Credit hours has been increased? Is it different by FTIC students and Non-FTIC students?
Dependent Variable: Number of Credit Attempted
Source SS MS F
Sig.
STRM
210.0
105.0
7.4
0.00
FTIC
1219.8
STRM * FTIC
1364.8
682.4
48.3

20. Categorical Data Chi-Square (χ2) Logistic Regression
Examples of burning research questions:
Is there a relationship between Ethnicity and persistence (Yes/No)?
There are some differences between tutored students and non-tutored students on their success on the course (yes/no).

21. Chi-Square (χ2)
Tutored students showed better completion and success rate?
Independent: Turtored/Non Tutored
Dependent: Complete/Non-Complete Success/Non-Success

22. More Advanced Analysis
Regression Discontinuity

23. Structural Equation Modeling
LASSI MOT
LASSI ATT
Self-efficacy
FTO E5
INP
Motivation E6
0.28*** /0.30*** d1
TST E7
Cognitive Skill Strategies
0.47*** /0.39***
0.19***
SMI d2
0.13 E8
TMT
Self-regulation
Strategies
Academic Achievement E9
0.02
SFT
E10 d3
CON

24. And what are you going to do about it?
So, what’s your data?
And what are you going to do about it?

25. Thank you
Questions?
More Information?