Question

	Observed (O)	Expected (E)	(O-E)2	(O-E)2/E
Woody Plants	28	19.4	73.96	3.812371
Grasses	25	19.4	31.36	1.616495
Other Herbaceous Plants (not grasses)	18	19.4	1.96	0.101031
Agricultural Plant Materials (corn, ets.)	15	19.4	19.36	0.997938
Arthropods	11	19.4	70.56	3.637113
			Chi-square	10.16495
			Chi-square Test	0.037739

Did I calculate the chi-square test correctly?

How do I report and interpret the results?

Answer 1

Here' the answer to the question. Please let me know in case you've understood the answers correctly.

Yes, you have calculated the chisquare rightly.

First off, the ChiSquare calculated as the summation of all (O-E)^2 /E would lead you to a value of 10.16495

Second, you can apply the Chisquare p-value Excel formula as = 1- CHISQ.DIST(10.16495,4,TRUE)

= 1-.962261

= 0.037739, which is the answer you have got.

To present & interpret the result, you should say:

The p-value is less than .05 ( assumed alpha / critical value), which can be interpreted as "the distribution of Woody Plants is not uniform"