# Chi Squared Test watch

1. Ok, here is the data:

conditions Observable Number
Dark,Light 7, 12, 7, 5, 6, 4, 5, 5, = 51
Dark,Dry 18, 37, 18, 31, 33, 16, 17, 16, =186
Wet,Light 4, 4, 7, 9, 4, 6, 4, 8, = 46
Wet,Dark 31, 7, 26, 15, 17, 30, 32, 19, = 177

Ok, the null hypothesis is that the conditions do not affect the observable number of woodlice seen in each environment

so expected numbers is the total divided by 4 = 115

can someone calculate chi squared and tell me what they got so i can compare?

WHAT IS THE DEGREE OF FREEDOM??
2. degree of freedom is v=m-1xn-1
3. do you have a level of significance? for the question
4. (Original post by samzurai)
degree of freedom is v=m-1xn-1
is it 18?
5. (Original post by samzurai)
do you have a level of significance? for the question
can you tell me what that is?
6. (Original post by smetin92)
is it 18?
no its 1
7. (Original post by smetin92)
can you tell me what that is?
the perecentage of error?
8. If you're doing A level biology, then I believe the degree of freedom is 3. No. of groups(in this case 4) - 1 = 3
and you look at the stats table.
null hypothesis is that there's no difference between expected and observed data and that any difference is due to chance - insignificant.
9. CHI Squared = sum of (O-E)^2 divided by sum of (E)

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