In: Statistics and Probability
One way to write the research hypothesis for the independent-measures t-test is:
The independent samples t test (also called the unpaired samples t test) is the most common form of the T test. It helps you to compare the means of two sets of data. For example, you could run a t test to see if the average test scores of males and females are different; the test answers the question, “Could these differences have occurred by random chance?”
Assumption of Independence: you need two independent,
categorical groups that represent your independent variable. In the
above example of test scores “males” or “females” would be your
independent variable.
Assumption of normality: the dependent variable should be
approximately normally distributed. The dependent variable should
also be measured on a continuous scale. In the above example on
average test scores, the “test score” would be the dependent
variable.
Assumption of Homogeneity of Variance: The variances of the
dependent variable should be equal.
If M1 and M2 be the true population means for two independent groups of variables,
to test, H0:Means are equal or
H0:M1=M2
vs
H11:Means are unequal
H11:M1M2
or H12:Mean of 1st population is less than that of 2nd population.
ie H12:M1<M2
or H13:Mean of the 1st population is greater than that of 2nd population.
or H13:M1>M2.
If there is any understanding problem regarding this please feel free to ask any doubt in comment box. Thanks.