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# Data Analysis

Data Analysis. M. Burns FCS 5470. Functions of Statistics. Describe what data look like – descriptive Allow for inferences to be made to a larger population – inferential Which would be more appropriate for evaluation?. Factors influencing analysis selection. Key questions

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## Data Analysis

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1. Data Analysis M. Burns FCS 5470

2. Functions of Statistics • Describe what data look like – descriptive • Allow for inferences to be made to a larger population – inferential • Which would be more appropriate for evaluation? Jones & Kottler, 2005

3. Factors influencing analysis selection • Key questions • Nature of data • Single-group v multi-group data • Continuous v discrete variables • Nominal, ordinal, interval v ratio data • Reflects a normal distribution Jones & Kottler, 2005

4. Scales of measurement • Nominal • Identify different categories of people, objects, etc. • Ordinal • Reflect a particular order or sequence • Interval • Reflect standard and equal units of measurement • Ratio • Similar to interval, but has a true zero point Jones & Kottler, 2005

5. Normal Distribution Leedy & Ormond, 2001

6. Descriptive Statistics • Measures of central tendency • Mean, median, mode • Measures of variability • Range, standard deviation, quartile deviation • Measures of association • Correlation co-efficient Jones & Kottler, 2005

7. Measures of Central Tendency • Mean • Average performance • Only appropriate for interval or ratio data • Median (m) • Middle score • Most appropriate for ordinal data • Mode • Score that occurs most often • Only appropriate for nominal data Jones & Kottler, 2005; Leedy & Ormond, 2001

8. Measures of Variability • Range • Spread of the data from lowest to highest value • Range = Highest score – lowest score • Quartile range (OIR) • Divide the distribution into four equal parts (quartiles) based on the median or mean • Difference between the 25th and 75th percentiles is calculated Leedy & Ormond, 2001

9. Measures of Variability • Standard deviation (SD) • Used to describe how different the scores in the group are from each other • Numeral that represents the average difference between each score and the mean • Most appropriate for normally distributed data • Average of the difference between the scores and the mean of the scores Jones & Kottler, 2005

10. Measures of Association • Correlation coefficient • Single numeral that describes the relationship between scores or r • Number between -1 (negative or inverse correlation) and +1 (positive correlation) • Direction v strength Jones & Kottler, 2005

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