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This chapter covers the steps and techniques involved in analyzing and interpreting quantitative data, including descriptive and inferential analysis. It also discusses how to report and discuss the results, including using tables, figures, and providing detailed explanations.
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Chapter 7 Analyzing and Interpreting Quantitative Data Power Point Slides by Ronald J. Shope in collaboration with John W. Creswell
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
How do you analyze the data? Conduct descriptive analysis • Conduct descriptive analysis • Measures of central tendency • Measures of variability • Measures of relative standing Educational Research 2e: Creswell
Run Descriptive statistics DescriptiveStatistics Central Tendency Variability Relative Standing Mean Median Mode Variance Standard Deviation Range Z-Score Percentile Ranks Educational Research 2e: Creswell
Conduct inferential analysis • Hypothesis testing Educational Research 2e: Creswell
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
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 Mann- Witney U-Test Kruskall Wallis Test Friedman Two-Way Anova Pearson Correlation Coefficient Regression Coefficient Discriminant Analysis Point Biserian Correlation T-Test Analysis of Variance Analysis of Covariance Spearman Rho Kendall’s Tau Educational Research 2e: Creswell
Normal Curve 34% 34% 13.5% 13.5% 2.5% 2.5% Mean +1 -3 -2 -1 +2 +3 Standard Deviations 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
Decision made by the Researcher Based on the Statistical Test Value State of Affairs in the Population Effect Exists Null False No Effect- Null True Type I Error (false positive) (probability= Alpha) Correctly rejected no error (probability= power) Reject the Null Hypothesis Correctly not rejected no error Type II Error (false negative) (probability= Beta) Fail to Reject the Null Hypothesis Outcomes of hypothesis testing: Type I and type II errors Educational Research 2e: Creswell
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
How do you discuss the results? • Summarize major results • Explain why they occurred • Advance limitations • Suggest future research Educational Research 2e: Creswell