the simple variance used to measure the spread of values in a single 

 data set. It is also sometimes called the standard error of the estimate. 

 The value produced by regression to indicate uncertainty of the esti- 

 mated y; the value Sy.^^ depends on the variances of all the estimated 

 coefficients. 



t The t-value produced in simple regression to test whether the estimated 



regression coefficient is "significantly" different from zero. 



H 



V longshore current velocity 



X independent variable in regression 



X observed values of X. A string of n-values in simple regression; a 

 n by p matrix in multiple regression 



Y dependent variable to be estimated 

 y n observed values of Y 



y estimated value of Y for given values of X 



a Y- intercept in a regression model 



at angle between the crest of the breaking wave and the shoreline 



§ estimated regression coefficients in multiple regression or the slope of 

 the line in simple regression 



Z(x - x)(y - y) ^ 



B = ■:^ — (Model I) 



Z(x - x)2 



B = -^2 (Model II) 

 e zero-mean random component of Y assumed by both regression models 



