The t-Test (AQA A-Level Further Maths): Quizzes

When population variance is unknown

$14$

To make it an unbiased estimator

$t = \frac{\bar{X} - \mu_0}{S/\sqrt{n}}$

Heavier tails

When sample size $n \geq 30$

Normal population & random sample

$6\%$

$\bar{X} \pm t \times \frac{s}{\sqrt{n}}$

Sample mean used in variance calculation