Question

The income of brokers in Barbados is normally distributed. A sample of 54 brokers has an

average yearly income of BD$86,000 with standard deviation of BD$12,000. Find the

98% confidence interval for the yearly mean income of Barbadian brokers.

Answer 1

We have given that,

$n = 54$

$\bar x = 86000$

$s = 12000$

Confidence interval can be calculated as

$CI = \bar x \pm z \dfrac{s}{\sqrt n}$

$CI = 86000 \pm 3802.72$