Wald Chi Square. Of the bonding agents tested significantly higher mtbs was obtained with the total etch 2 stage adhesive. The generalized wald chi square statistic is computed as where is an array of r 1 c 1 differences between the observed and expected weighted frequencies and estimates the variance of.
Is the covariance matrix of the estimates and its computation is described in the section covariances of frequency estimates. I am not clear why we use chi square and not t statistics like in linear regression. Wald chi square statistisc estimate std error 2 the null hypothesis is tested using chi square distribution.
Where w2 is the wald statistic that asymptotically follows a chi square distribution with rank l as the degrees of freedom.
Look at the estimates large for variable 5 compared to the reference category with realtively small standard errors. The results of this study suggest that there are similar bond strengths between the 1 and 2 bottle self etch. Of the bonding agents tested significantly higher mtbs was obtained with the total etch 2 stage adhesive. Look at the estimates large for variable 5 compared to the reference category with realtively small standard errors.
