What is quantitative data?
Numerical information that can be measured and statistically analyzed.
Understanding the difference between these types is crucial for selecting appropriate methods of data collection and analysis.
Descriptive statistics summarize and organize data to describe the main features of a dataset.
Standard Deviation (SD): SD is the most informative measure of dispersion as it measures the average variability around the mean.
Different graph types serve various purposes depending on the data type and relationships being shown.
Normal Distribution Baseline: Symmetrical and bell-shaped, with Mean = Median = Mode. Many statistical tests assume this shape.
The magnitude (absolute value) indicates the strength of the linear association.
| Range | Strength | Range | Strength |
|---|---|---|---|
| 0.0 to ±0.1 | very weak | ±0.5 to ±0.7 | strong |
| ±0.1 to ±0.3 | weak | ±0.7 to ±1.0 | very strong |
| ±0.3 to ±0.5 | moderate |
The level describes the nature of the data and affects which statistical analyses are appropriate.
Coding involves categorizing data into units that represent meaningful concepts, transforming qualitative data for systematic analysis.
What is quantitative data?
Numerical information that can be measured and statistically analyzed.
Give examples of quantitative data.
Reaction times, IQ scores, height, number of correct answers.
What is qualitative data?
Descriptive, non-numerical information capturing meanings and experiences.
Name common qualitative data collection methods.
Interviews, open-ended questionnaires, observations, content analysis.
What distinguishes primary data?
Data collected firsthand by the researcher for their specific study.
What is secondary data?
Data originally collected by others for different purposes.
Define meta-analysis.
Statistical combination of results from multiple primary studies.
What are measures of central tendency?
Mean, median, and mode.
How is the mean calculated?
Sum of all scores divided by the number of scores.
What does standard deviation measure?
The average amount of variability or spread around the mean.
What type of graph shows paired quantitative data points?
Scattergram (scatterplot).
Describe a normal distribution.
Symmetrical, bell-shaped distribution where mean = median = mode.
What does a positive correlation indicate?
Both variables increase together.
Name the three levels of measurement.
Nominal, ordinal, and interval.
What is coding in content analysis?
Categorizing qualitative data into units for analysis.