Question

A study of the annual growth of certain cacti showed that 20 of them, selected at random in a desert region, grew on the average 52.80 mm with a standard deviation of 4.50 mm. Construct a 95% confidence interval for the true average annual growth of the given kind of cactus. Round your final answer to three decimal places.

Answer 1

Solution :

Given that,

t /2,df = 2.093

Margin of error = E = t/2,df * (s /n)

= 2.093 * (4.50 / 20)

Margin of error = E = 2.106

The 95% confidence interval estimate of the population mean is,

- E < < + E

52.80 - 2.106 < < 52.80 + 2.106

50.694 < < 54.906

(50.694 , 54.906)