Question

Please do chi-square analysis of the following:

Experiment 1: without heat lamp							Experiment 2: with heat lamp
	Soil	Leaves	Rock	Other				Soil	Leaves	Rock	Other
Expected	5	5	5	0			Expected	5	5	5	0
Observed	10	3	2	0			Observed	1	5	9	0

Answer 1

Chi square test for goodness of fit

Solution:

Required table for calculation is given as below:

Experiment 1: without heat lamp
	Soil	Leaves	Rock	Other	Total
Expected (E)	5	5	5	0
Observed (O)	10	3	2	0
(O - E)	5	-2	-3	0
(O - E)^2/E	5	0.8	1.8	0	7.6

Chi square = ∑[ O - E)^2/E] = 7.6

df = 4 – 1 = 3

P-value = 0.055044

P-value > α = 0.05

So, we conclude that expected distribution and observed distribution are approximately same.

Second test:

Experiment 2: with heat lamp
	Soil	Leaves	Rock	Other	Total
Expected (E)	5	5	5	0
Observed (O)	1	5	9	0
(O - E)	-4	0	4	0
(O - E)^2/E	3.2	0	3.2	0	6.4

Chi square = ∑[ O - E)^2/E] = 6.4

df = 4 – 1 = 3

P-value = 0.093691

P-value > α = 0.05

So, we conclude that expected distribution and observed distribution are approximately same.

(P-values are calculated by uisng Chi square table or excel)