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What statistical test is used to compare means?
compare means t-test
The compare means t-test is used to compare the mean of a variable in one group to the mean of the same variable in one, or more, other groups. The null hypothesis for the difference between the groups in the population is set to zero. We test this hypothesis using sample data.
How do you determine if the difference between two numbers is significant?
The t-test gives the probability that the difference between the two means is caused by chance. It is customary to say that if this probability is less than 0.05, that the difference is ‘significant’, the difference is not caused by chance.
When to use average instead of sum scores?
A list of behaviors (no, yes) is more logic with a sum score. A practical justification for using average instead of sum scores: if you use sum scores you need to be sure that when comparing the sums all the individuals responded to the same number of questions/items.
When to use one sample t-test in statistics?
A one sample t-test allows us to test whether a sample mean (of a normally distributed interval variable) significantly differs from a hypothesized value. For example, using the hsb2 data file, say we wish to test whether the average writing score ( write ) differs significantly from 50.
How to decide which statistical test to use?
In deciding which test is appropriate to use, it is important to consider the type of variables that you have (i.e., whether your variables are categorical, ordinal or interval and whether they are normally distributed), see What is the difference between categorical, ordinal and interval variables? for more information on this.
When to use independent samples in statistical analysis?
An independent samples t-test is used when you want to compare the means of a normally distributed interval dependent variable for two independent groups. For example, using the hsb2 data file, say we wish to test whether the mean for write is the same for males and females. t-test groups = female (0 1) /variables = write.