Stats Tests Flashcards
When would you use correlation coefficient
When investigating the relationship between two variables
It will say correlation
(Taking measurements)
When would you use T test
When investigating a difference between two means
(Taking measurements)
When would you use chi squared
When investigating the difference between two numbers of individuals
(Counting how many individuals in a category)
What does it mean if the SDs do not overlap
There is a significant difference
Difference is not due to chance
What does it mean if the SDs overlap
no significant difference
Difference is due to chance
How do you write a null hypothesis eg investigating effect of antibiotics on lung cancer of mice
The antibiotics have no effect on the treatment of lung cancer in mice
Describe how to use a stats test to find whether there is a correlation
- Write a null hypothesis
- Use CC and calculate test statistic
- Look up in table to find critical value of P=0.05
- Use figure to accept or reject null hypothesis
what does it mean if the calculated value is more than or equal to the critical value (P=0.05)
- there is less than 5% probability that the results are due to chance
- difference is significant
- reject the null hypothesis
what does it mean if the calculated value is less than the critical value (P=0.05)
- there is more than 5% probability that the results are due to chance
- difference is not significant
- accept the null hypothesis