Statistical Power calculations for z-test for two independent samples.
currently only uses pooled variance
plot_power([dep_var, nobs, effect_size, ...])
Plot power with number of observations or effect size on x-axis
power(effect_size, nobs1, alpha[, ratio, ...])
Calculate the power of a z-test for two independent sample
solve_power([effect_size, nobs1, alpha, ...])
solve for any one parameter of the power of a two sample z-test