RESEARCH · METHODS · EVIDENCE
Center and spread
Browse statistics lessons
- Statistics for research
- Center and spread
- Distributions and standard errors
- Statistical inference
- P-values and interpretation
- Critical values and test direction
- Compare means with t-tests
- Read t-test output
- Compare several means with ANOVA
- Read an ANOVA table
- Analyze categorical counts
- Read chi-square output
- Describe an association
- Read correlation results
- Interpret a regression model
- Choose a statistical method
- Statistics resources
The mean uses all numeric observations; the median is the middle ordered value; the mode is the most frequent value and may not be unique. Describe variability as well as location. A skewed distribution or influential outliers can make the mean unrepresentative.
In the Excel practice scores 5, 4, 5, 2, 1, the mean is 3.4, the median is 4, and the sample standard deviation is about 1.82. These describe a teaching dataset; the variable’s measurement scale determines what summaries are meaningful.
References: NIST statistical handbook