Symbols – CSU Stats Tutor

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.

Name	Symbol	Description
Population Mean	$\mu$	A parameter, the population average.
Sample Mean	$\bar{x}$	A statistic, the sample average.
Population Standard Deviation	$\sigma$	A parameter, which measures the variability in the population.
Sample Standard Deviation	$s$	A statistic, which measures the variability in the sample
Sample Size	$n$	The number of observations in an experiment.
Pooled Standard Deviation	$s_p$	A weighted average of two groups standard deviations.
T Value	$t$	Can represent a test statistic when performing a t-test or the critical value when creating a CI.
Z Value	$Z$	Can represent a z-score or a test statistic.
Sample Correlation	$r$	Measures the linear relationship between two variables.
Population Correlation	$\rho$	Measures the linear relationship between two variables.
Proportion	$p$	The number of "successes" over the total observations.
Null Hypothesis	$H_o$	The assumed hypothesis when performing a hypothesis test.
Alternative Hypothesis	$H_a$	The hypothesis we are trying to "disprove" in a hypothesis test.
Estimated Slope	$b_1$	The estimated slope in the line of best fit.
Estimated Y-Intercept	$b_o$	The estimated y-intercept in the line of best fit.
Population Slope	$B_1$	The theoretical slope in a linear regression model.
Population Y-Intercept	$B_0$	The theoretical y-intercept in a linear regression model.
Coefficient of Determination	$R^2$	The proportion of variability in the response that can be explained by the model.
Random Error	$\varepsilon$	The random error term that is added in the theoretical linear regression model.
F Value	$F$	The test statistic used when performing ANOVA.