1. Analyzing and Interpreting Quantitative Data
Chapter 7
Analyzing and Interpreting Quantitative Data
Power Point Slides by Ronald J. Shope in collaboration with John W. Creswell

2. Steps in quantitative analysis and interpretation
How do you analyze the data?
How do you report the results?
How do you discuss the results?
Educational Research 2e: Creswell

3. How do you analyze the data? Conduct descriptive analysis
Measures of central tendency
Measures of variability
Measures of relative standing
Educational Research 2e: Creswell

4. Run Descriptive statistics
Central Tendency
Variability
Relative Standing
Mean
Median
Mode
Variance
Standard Deviation
Range
Z-Score
Percentile Ranks
Educational Research 2e: Creswell

5. Conduct inferential analysis
Hypothesis testing
Educational Research 2e: Creswell

6. Conduct hypothesis tests
Identify a null and alternative hypothesis
Set the level of significance (alpha level) for rejecting the null hypothesis
collect data
Compute the sample statistic
Make a decision about rejecting/failing to reject
Educational Research 2e: Creswell

7. Computing the sample statistic
Inferential Statistics
Continuous (iv)
Continuous (dv)
Continuous (iv)-
Continuous (dv)
Continuous (iv)-
Continuous (dv)
Continuous (iv)-
Continuous (dv)
Parametric
Parametric
Parametric
Chi-Square
Analysis
Phi
Coefficient
Nonparametric
Nonparametric
Nonparametric
Pearson
Correlation
Coefficient
Regression
Mann-
Witney
U-Test
Kruskall
Wallis Test
Friedman
Two-Way
Anova
Discriminant
Analysis
Point
Biserian
Correlation
T-Test
Analysis of
Variance
Covariance
Spearman
Rho
Kendall’s
Tau
Educational Research 2e: Creswell

8. Educational Research 2e: Creswell
Normal Curve
34%
34%
13.5%
13.5%
2.5%
2.5%
Mean -3 -2 -1 +1 +2 +3
Standard Deviations
Educational Research 2e: Creswell

9. Educational Research 2e: Creswell
The Normal Curve of Means Differences of All Possible Outcomes if the Null Hypothesis is True
Reject the
Null
Hypothesis
Reject the
Null
Hypothesis
High Probability
Values if the Null
Hypothesis is True
Extremely low
Probability Values
if Null Hypothesis
is True (Critical
Region)
Extremely low
Probability Values
if Null Hypothesis
is True (Critical
Region)
Alpha=.025
Alpha=.025
Two-Tailed Test
Educational Research 2e: Creswell

10. Outcomes of hypothesis testing: Type I and type II errors
State of Affairs in the Population
Decision made by
the Researcher
Based on the
Statistical Test
Value
Type I Error
(false positive)
(probability=
Alpha)
Correctly not
rejected
no error
Correctly
power)
Type II Error
(false negative)
Beta)
Reject the
Null
Hypothesis
No Effect-
Null True
Effect Exists
Null False
Fail to Reject the
Null Hypothesis
Educational Research 2e: Creswell

11. How do you report the results?
Tables summarize statistical information
Figures (charts, pictures, drawings) portray variables and their relationships
Detailed explanations about statistical results
Educational Research 2e: Creswell

12. How do you discuss the results?
Summarize major results
Explain why they occurred
Advance limitations
Suggest future research
Educational Research 2e: Creswell