Week 4 Confidence intervals and hypothesis testing Flashcards
What is standard error?
Provides an indication of how well your sample represents the population (lower the more representative)
How does the sample size effect sampling error?
Lower the sampling error
What is a confidence interval?
An estimated range of value which is 95% likely to include the REAL population mean
What is a null hypothesis?
States that there will be no difference between the means or no relationship between variable.
What is an alternative hypothesis?
States that there will be a difference between the means or a relationship between variable.
We cannot prove that the alternative hypothesis is true, but what can we do?
Demonstrate that the alternative hypothesis is sufficiently more likely than the mull hypothesis given
What do the significance level and the probability values determine?
Whether we reject the null hypothesis or fail to reject the null hypothesis
What is the level of significance typically set at?
5%, alpha = 0.05
What is a type 1 error?
You conclude there is a difference when, in reality, there isn’t
What is a type 2 error?
You conclude there is no difference when, in reality, there is.
What is the p value typically set at?
5% or p=0.05
What does a small p value mean?
There is a lower probability that the observed difference was due to chance
What does it mean if the p-value is less than the selected significance value?
We are confident that the observed difference reflects a real difference between the two population of interest
What happens if p=0.03 (p<0.05)?
We reject the null hypothesis and interpret the result as real, there is a 3% chance the difference is down to chance
How should you interpret the p-value if it is p>0.10 to 1.00?
No evidence against the null hypothesis
