Compare two means

Question 1

what is this for?

Answer 1

deciding whether data in two columns can be related in pairs

Question 2

matched or paired-sample t test

Answer 2

used when data is naturally in a pair such as before and after or matched pairs

in excel: data analysis, t-test, paired two sample for means, select variables tick labels, output range, ok

Question 3

two-sample test: comparing two means (unpaired data)

Answer 3

• data from each of the samples is independent to each other
• the goal of inference is to compare the responses of two groups
• each group is considered to be a sample from a distinct population
• the responses in each group are independent to those in the other group

Question 4

two samples z statistic (sigma is known) for unpaired

Answer 4

null: mean 1 = mean 2 or mean 1 - mean 2 = 0
alternative: means are not equal or one is smaller or larger than the other

nasty many stories equation

Question 5

two samples t statistic (sigma is known) for unpaired

Answer 5

same as z but with s

Question 6

two sample t procedures (sigma not known) for unpaired

Answer 6

assume populations have normal distributions

there is a nasty equation that requires t tables to get confidence intervals