These are the symbols that will be used in this course. They are ordered approximately related to order of modules where the symbol was introduced.
Symbol Definition
 N

Population size. [
generally unknown ]  n
 Sample size.
 x_{i}
 Value of the X variable for the ith individual.
 \(\bar{\textrm{x}}\)
 Sample mean (average) of the X variable.
 s
 Sample standard deviation.
 s^{2}
 Sample variance.
 M

The sample median. [
rarely used ]  Q1
 First quartile.
 Q3
 Third quartile.
 IQR
 Interquartile range (Q3Q1).
 μ
 Population mean.
 σ
 Population standard deviation.
 X~N(μ,σ)
 The variable X is normally distributed with a mean of μ and standard deviation of σ.
 N(0,1)
 Standard normal distribution.
 c
 The number of columns in a twoway frequency table.
 r
 The sample correlation coefficient OR number of rows in a twoway frequency table.
 r^{2}
 The coefficient of determination.
 \(\hat{\textrm{y}}_{\textrm{i}}\)
 Predicted value of the response variable (in regression).
 RSS
 Residual sumofsquares.
 H_{0}
 The null hypothesis.
 H_{A}
 The alternative hypothesis.
 α
 The rejection criterion OR probability of making a Type I error.
 β
 The probability of making a Type II error.
 C
 The level of confidence for a confidence region.
 Z
 A variable that follows a N(0,1) OR the test statistic in a onesample Ztest.
 μ_{0}
 Specific value of μ in the H_{0} of 1Sample Z and tTests.
 t
 A variable that follows a tdistribution OR the test statistic in ttests.
 s_{p}^{2}
 Pooled sample variance in a 2Sample tTest.
 σ^{2}
 Population variance.
 df
 Degreesoffreedom.
 χ^{2}
 A variable that follows a chisquare distribution OR the test statistic in chisquare tests.
 p
 Population proportion of successes.
 \(\hat{\textrm{p}}\)
 Sample proportion of successes.