Air qualility

a_i

n_1i

n_0i

m_1i

m_0i

T_i

e_i

$s_i^2$

Good

80

461

134

93

502

595

72.0555

13.7142

Fair

145

787

220

171

836

1007

133.6415

24.2629

Poor

62

272

126

86

312

398

58.7739

14.6230

∑_i

287

1520

480

350

1650

2000

264.4708

52.6001