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Statistics in Small Doses

Statistics in small doses: Does (sample) size matter?

Statistics in small doses: Does (sample) size matter?

The goal this month is to relate the importance of sample size as told by investigators and statisticians themselves. Sample size can cause considerable difficulty ... Full story

What are the Type I and Type II errors?

What are the Type I and Type II errors?

Recall that we test the null hypothesis, H0. If a difference actually does not exist, H0 would be true, and it would be correct to ... Full story

What are null and alternative hypotheses?

What are null and alternative hypotheses?

For most studies, investigators have particular research questions that they would like to address. For instance, an investigator may wonder whether a new drug can ... Full story

What are Parametric and Nonparametric Statistical Tests?

What are Parametric and Nonparametric Statistical Tests?

Both parametric and nonparametric tests can be used to evaluate hypotheses, and choice of which procedure to use depends on the type of variable analyzed ... Full story