t-statistics test

2019

2020

2021

Mean Difference

0.0327

0.0233

0.0231

Standard Error

0.0104

0.0137

0.0131

t value

3.1337

1.7037

1.7682

Degree of Freedom

208

225

256

Critical Value

1.6522

1.6516

1.6508

R-squared

0.0451

0.0127

0.0121