\( H_0: \mu = \mu_0 \)

\( \chi^2 = \sum \frac{(O_i - E_i)^2}{E_i} \)

\( t = \frac{\bar{x} - \mu}{s/\sqrt{n}} \)

\( r = \frac{\sum (x_i - \bar{x})(y_i - \bar{y})}{\sqrt{\sum(x_i-\bar{x})^2 \sum(y_i-\bar{y})^2}} \)

\( E = mc^2 \)

\( F = ma \)

\( V = IR \)

\( a^2 + b^2 = c^2 \)