The Student Room Group
To see if results are statistically significant and weather to reject or accept the null hypthesis.
Reply 2
is it possible to have a chi-squared figure of 200+?? The answer to me just seems a little odd, not sure if im doing it right.
Reply 3
OK can any tell me what it would mean then if i had a chi-squared of 200+ with one degree of freedom?
Monkey_Boy
OK can any tell me what it would mean then if i had a chi-squared of 200+ with one degree of freedom?


http://helios.bto.ed.ac.uk/bto/statistics/table2.html#Chi%20squared%20test

It means you reject your null hypothesis.
Reply 5
Monkey_Boy
is it possible to have a chi-squared figure of 200+?? The answer to me just seems a little odd, not sure if im doing it right.


The point of doing a Chi-squared test or a T-test (either paired or unpaired) is to get a p-value or a confidence interval.

The p-value is between 0 and 1 - (so no, a value of 200 for a p-value is wrong)

The p-value is the probability that the results are due to chance

e.g. a p-value of 0.06 means that there is a 6% chance that your results are due to chance.

If you have p<0.05

this means that the probability that the results is due to chance is less than 5%, which means that you can reject the null hypothesis since there is likely to be a relationship between the factors you are investigating

p>0.05

means that there is a probability that the results are due to chance is greater than 5% - which does NOT mean that you accept the null hypothesis, but instead "there is not enough evidence that the results are not due to chance and so you cannot reject the null hypothesis"! (confusing as hell I know)


You can also use confidence intervals to access the null hypothesis but I don't think you can do this for a Chi-squared test because you aren't measuring a quantitative variable - well you shouldn't be but I dunno what you are investigating so i can't really tell