Criteria for choosing the correct test:
t test of means:
–values are continuous
–there is no reason why a particular value in one group would be related to a particular value in the other group
–comparing two group means
paired t test:
–values are continuous
–there is a connection between particular values in one group and corresponding values in the other group
–comparing differences between pairs of values in the two groups
linear regression:
–values are continuous
–values representing the experimental factor vary continuously rather than fall into discrete categories
–determining whether the line of best fit has a slope greater than zero
Appropriate null hypotheses for the statistical tests discussed:
t test of means:
–The means of the two groups are the same (i.e. differences in sample means are due only to chance).
paired t test:
–The difference between pairs of blocked data is zero (i.e. pairs of blocked data deviate randomly)
linear regression:
–The slope of the best fit line through the data is zero (i.e. deviations from a best-fit line having slope of zero are random).
