Perform a test that will compare all four means at once we

Question

Consider the sample data for plants A, B, C & D of the above company, which are tabulated in table 1.

Test whether the four means are equal at the 5% level of significance.

Perform a test that will compare all 4 means at once. We are not interested in pair-wise comparisons at this stage. Please show all the steps in your calculations.

Table 1:

A	B	C	D
333	328	320	333
332	329	321	321
320	323	322	329
326	327	325	330
328	330	326	328
325	331	328	325
323	332	329	333
321	320	330	331
334	324	331	327
322	323	332
320	334
329
330
328
331
330