#STATA 13 HELP HOW TO#
#STATA 13 HELP SOFTWARE#
#STATA 13 HELP TV#

Later on in this presentation we will cover many different types of effect sizes, but the point here is that you are interested in the size of the effect, not in the statistical significance. But if my drug only reduces blood pressure by one point, you say вЂњso what, your effect size is too small to matter in the real world.вЂќ And you would be correct, even if I ran a huge study with 1000s of participants to show a statistically significant effect. So for example, letвЂ™s say that I invented a new drug to lower blood pressure. When you ask a statistician that question, what the statistician hears is вЂњI want to know the effect size.вЂќ According to Wikipedia, вЂњin statistics, an effect size is a quantitative measure of the magnitude of a phenomenon.вЂќ ( ). What you want to know is if the treatment matters in the real world. Adding more participants to a study doesnвЂ™t make a treatment more or less effective. So, in general, as N goes up, the p-value goes down, holding everything else (e.g., alpha, effect size) constant.Д«ut this doesnвЂ™t really answer your question. And most statisticians realize that this p-value is closely related to the number of participants, which is usually called N. In statistics (at least as it is practiced today) вЂњstatistical significanceвЂќ means that the p-value associated with the test statistic is less than. Now to a statistician, this is not surprising at all. So you do this, but then you notice something that seems a little odd: the greater the number of participants in a study, the more likely the study was to find a significant result. Now what do you do? You may decide that you are going to find all of the studies on this research question and count up how many found significant results and how many did not. You find that some of the studies replicated the results while others did not (i.e., failure to replicate results). So letвЂ™s say that this topic is something that you really care about, and you wait to hear more results from the replication studies. Almost always, there is a quote from one of the studyвЂ™s authors saying that вЂњthis research needs to be replicated with more subjects before anyone should act on the results.вЂќ And we all nod our heads, because we know that replication is an important part of the foundation of the scientific method. Some new drug, or treatment, or something, has been shown to do something.

#STATA 13 HELP TV#

HereвЂ™s an experience we can all relate to: you read about a study on your favorite news website, or hear about it on TV or the radio. Remember that this is a brief introduction to this topic, so we will only briefly touch on many important topics that might be worthy of an entire workshop unto themselves. I assume that you are familiar with basic descriptive statistics, such as means and standard deviations what an odds ratio is what heterogeneity means. Will not cover any of the more advanced topics, such as multiple imputation of missing data or multilevel meta-analysis Assumptions

#STATA 13 HELP HOW TO#

How to access and/or use electronic databases

#STATA 13 HELP SOFTWARE#

This is not an introduction to the use of Stata software This is not a hands-on workshop we will not be running the commands today Resources for further information What not to expect How to run a meta-analysis and interpret the resultsДЄ brief discussion of the different types of biases that may compromise the results of a meta-analysis

Information on how to collect data for a systematic review and/or meta-analysis

Definition of systematic review and meta-analysis

Stata 13 help