which of the following t distributions represents a confidence interval? if the variance is unknown what is the confidence interval for the unpaired sample why use the t distribution for confidence interval for difference of variance for unpaired samples? what is the t distribution for variance of the t distribution how to deduce what to use for confidence interval why use t distribution for confidence interval for unpaired sample what is the confidence interval used for t distribution when does the rst use the t distribution? where is the t distribution used for confidence interval? which statement best describes the confidence interval for the variance test? why use t-distribution for confidence interval for difference of means for unpaired samples? when t distribution is used how to derive confidence interval for unpaired samples what is a t distribution why use the t distribution for confidence interval? why use the t-distribution for confidence interval for unpaired samples? t distribution for confidence interval for variance is why use t distribution why use the t distributions how do you find the confidence interval of a sample when the variance is unknown