this is correct?

A study wants to compare the number of particles between good and bad wafers at a semiconductor manufacturing facility. Of 334 good wafers, 28 have particles. Of 116 bad wafers, 36 have particles.

At the = 0.05 level of significance, is there evidence of a difference between the proportion of good wafers that have particles and that of bad wafers?

Particles/No Particles	Wafers
Good	Bad	Total
Particles	28	36	64
No Particles	306	80	386
Total	334	116	450

H₀: p₁ = p₂

H₁: p₁ p₂

Observed Frequencies

The observed frequencies are the frequencies in the cells (green colored) of the contingency table:

Particles/No Particles	Wafers
Good	Bad	Total
Particles	28	36	64
No Particles	306	80	386
Total	334	116	450

Expected Frequencies

The expected frequency in a cell is the product of its row total and column total, divided by the overall total. Applying the formula to the example, we have the following expected frequencies:

Particles/No Particles	Wafers
Good	Bad	Total
Particles	64*334/450=47.50	64*116/450=16.50	64
No Particles	386*334/450=286.50	386*116/450=99.50	386
Total	334	116	450

Chi-Squared Statistic

Particles/No Particles	Wafers
Good	Bad	Total
Particles	28(47.50)	36(16.50)	64
No Particles	306(286.50)	80(99.50)	386
Total	334	116	450