INTRODUCTION TO ESTIMATING HOW MANY PARTICIPANTS ARE NEEDED 27/10/16 Flashcards
What is estimations?
finding an estimate of some variable of interest
Where do you estimate from and where do you extrapolate this to?
study sample and extrapolate this to your target population
How can estimates be measured? (2)
- means
2. frequencies
How do you measure the level of uncertainty in your estimate? (2)
- confidence interval
- standard error
What is hypothesis testing?
formal statiscal testing of a hypothesis
What is a null hypothesis?
no effect
what is an alternative hypothesis?
effect
How do medical studies test the hypothesis?
whether some average value differs from zero
How do we formally test hypotheses?
by calculating how likely our observations are under the null hypothesis
How is probability measured?
p value
null hypothesis is p<0.05
something being significantly different from the null hypothesis