Statistics Flashcards
What is a hypothesis?
A statement about the solution to a problem which has not yet been verified.
If rejected, null hypothesis confirmed.
What is a null hypothesis?
A statement which says the opposite of the hypothesis about the problem which has not yet been solved.
If rejected, hypothesis confirmed.
What is a power calculation?
Calculation of the ideal number of participants needed in a study for it to be reliable.
What is a significance level?
The point at which the statistics become significant - means not every possible participant has to be studied.
What does the empirical rule state?
68% of a population fall within 1 SD of the mean and 95% are within 2 SDs of the mean.
What does it mean when the significance level is 0.05 (5%)?
2.5% either side of the 95% of the population within 2 SDs of the mean
What does it mean when there is a significant difference between two groups?
The average of one group is within or outside of the extremes of the other group.
What does a two-tailed test mean?
Both ends of the population have been tested (2.5% either end)
What does a positive one-tailed test mean?
5% of the population has been tested at the upper end
What does a negative one-tailed test mean?
5% of the population has been tested at the lower end
If the p value is greater than the significance level (e.g. >0.05), what should be done?
Do not reject null hypothesis
If the p-value is less than the significance level (e.g. <0.05), what should be done?
Reject null hypothesis
What is ordinal data?
Categories can be put in an order, e.g. small, medium and large.
What is nominal data?
Data where categories have no scale or order (they have a name), e.g. eye colour.
What is continuous data?
Numerical data which can have any type of interval.
