Inference for a mean

Practicing Statistics Interview Questions in R

Zuzanna Chmielewska

Actuary

Inference for a mean

Inference for a mean

• confidence interval
• one-sample mean

Assumptions

The t-test's assumptions:

• normally distributed underlying data (recall CLT!)
• random sample
• independent observations

Confidence interval

Confidence interval

Confidence interval

Confidence interval

95% confidence interval

95% confidence interval

95% confidence interval

95% confidence interval

One-sample t-test

$$H_{0}: \mu = \mu_{0}$$

$$H_{1}: \mu \neq \mu_{0}$$

where:

$\mu$ - the population's mean

$\mu_{0}$ - the hypothesized mean

t-test in R

t.test(x)

t-test in R

t.test(x)

t-test in R

t.test(x)

t-test in R

t.test(x, mu = 2)

t-test in R

t.test(x, mu = 2, conf.level = 0.9)

Summary

• t-test's assumptions
• confidence interval
• one-sample t-test
• t.test() in R

Let's practice!

Practicing Statistics Interview Questions in R