General recall and understanding

definitions included

null hypothesis

type of hypothesis that states that there is no significant difference or correlation between things being investigated

student’s t-test

1. what it tests for

2. meaning of the value obtained

1. if there is a significant difference in the means of 2 data sets

2. value obtained is greater than critical value at a probability of 0.05, you can be 95% confident that the difference is significant and not due to chance

What is the 95% confidence limit?

95% is good enough for scientists to reject the null hypothesis

correlation coefficient (eg spearman’s rank)

1. purpose of the test

2. meaning of the value obtained

1. works out the degree to which 2 data sets are correlated

2. given as value from 1 to -1, where 1 means strong positive correlation, 0 means no correlation and -1 means strong negative correlation

result is compared to critical value to check if correlation is significant

chi-squared test

1. what does it test?

2. purpose of the test

3. meaning of the results

1. categorical data (grouped data)

2. checks if the results are statistically different from the expected results AKA to see if the results of an experiment support a theory

3. outcome of the results either supports or rejects the null hypothesis: chi-squared value is greater than or equal to critical value = reject null hypothesis and when chi-squared value is less than critical value = fail to reject null hypothesis