welch's t-test

  1. confused_pleasehelp

    two-sample assuming unequal variances - too sensitive?

    Hi there, I'm comparing image values in a tumour region before and after treatment. I'm trying to see if the value of the pixels is significantly different after treatment. The histogram distributions look like this (for one tumour): I assumed using the 'two-sample test assuming unequal...
  2. A

    Which test should I use for two unequal groups ?

    Hi all! I have data that include 20 samples divided into 2 groups (category A and category B). The groups are independent, none of the value in one group repeat in other. N(A) =14, N(B) = 6. here is the data: category A category B 0.0119888167559 0.023185483871...
  3. T

    comparing two independent binomial data sets, unequal size, Welchs t-test?

    I would like to compare the pass rates of two different classes (say English 111 and English 113). The data is binomial (0= fail, 1=pass). The sets are unequal size. I think its safe to assume independent population means and unknown SD. I am inclined to use Welch's t - test. But I am not sure...
  4. B

    Study review question for all you fellow biostat nerds. :)

    I'm thinking a welch's t-test is appropriate, but unsure of that? Can anyone lead me in the right direction? A geographer studying “hammock islands” (small patches of tropical hardwood forest) in the Florida Everglades was interested in determining the effect of invasion by the shrub...