STA 309 Chapter Notes - Chapter 12: Confidence Interval, Standard Deviation, Mean Absolute Difference
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Difference of means: = 1 - 2. If the sample means come from independent samples, the variance of their sum or difference is the sum of their variances. Two-sample t-test: use ratio of difference in the means from samples to its standard error to find a p-value from a t-model. H 0 : 1 - 2 = = 0. Two-sample t-interval: ( 1 - 2 ) t* df se( 1 - 2 ) Boxplots with boxes of approximately equal size. Standard deviation: se pooled ( 1 - 2 ) = s pooled. Degrees of freedom: df = (n 1 - 1) + (n 2 - 1) Pooled-t confidence interval: ( 1 - 2 ) t* df se pooled ( 1 - 2 ) Count how many values in high group are higher than all values of lower group. Add to number of values in low group that are lower than all the values of the higher group.