## Symbols

There are a lot of different symbols used in statistics. There could also be symbols you have used before in another class, but mean something different in stats. To clear some confusion, I compiled a list of the more common symbols used in intro CSU stat courses.

NameSymbolDescription
Population Mean A parameter, the population average.
Sample Mean A statistic, the sample average.
Population Standard Deviation A parameter, which measures the variability in the population.
Sample Standard Deviation A statistic, which measures the variability in the sample
Sample Size The number of observations in an experiment.
Pooled Standard Deviation A weighted average of two groups standard deviations.
T Value Can represent a test statistic when performing a t-test or the critical value when creating a CI.
Z Value Can represent a z-score or a test statistic.
Sample Correlation Measures the linear relationship between two variables.
Population Correlation Measures the linear relationship between two variables.
Proportion The number of "successes" over the total observations.
Null Hypothesis The assumed hypothesis when performing a hypothesis test.
Alternative Hypothesis The hypothesis we are trying to "disprove" in a hypothesis test.
Estimated Slope The estimated slope in the line of best fit.
Estimated Y-Intercept The estimated y-intercept in the line of best fit.
Population Slope The theoretical slope in a linear regression model.
Population Y-Intercept The theoretical y-intercept in a linear regression model.
Coefficient of Determination The proportion of variability in the response that can be explained by the model.
Random Error The random error term that is added in the theoretical linear regression model.
F Value The test statistic used when performing ANOVA.