$$se = \sqrt{ \frac{\pi (1-\pi)}{n} }$$
\[se = \sqrt{ \frac{\pi (1-\pi)}{n} }\]
$$\hat\pi \pm z se$$
\[\hat\pi \pm z se\]
$$ se_d = \sqrt{ \frac{\hat\pi_1 (1 - \hat\pi_1)}{n_1} + \frac{\hat\pi_2 (1 - \hat\pi_2)}{n_2} }$$
\[ se_d = \sqrt{ \frac{\hat\pi_1 (1 - \hat\pi_1)}{n_1} + \frac{\hat\pi_2 (1 - \hat\pi_2)}{n_2} }\]
$$\hat\pi_1 - \hat\pi_2 \pm z se_d$$
\[\hat\pi_1 - \hat\pi_2 \pm z se_d\]
$$se = s/sqrt{n}$$
$$\bar y \pm t se$$
\[\bar y \pm t se\]
$$ se_d = \sqrt{ \frac{s_1^2}{n_1} + \frac{s_2^2}{n_2} }$$
\[ se_d = \sqrt{ \frac{s_1^2}{n_1} + \frac{s_2^2}{n_2} }\]
$$\bar y_1 - \bar y_2 \pm t se_d$$
\[\bar y_1 - \bar y_2 \pm t se_d\]