Question

Orange trees ~ Orange trees are historically known to have mean circumference of 120 mm. A researcher randomly selected 35 orange trees and found that the sample mean circumference for the trees is 115.79 mm and the sample standard deviation is 57.81 mm. Note: Numbers are randomized in each instance of this question. Pay attention to the numbers in this question. The researcher wonders if the actual mean circumference of orange trees is less than the historic value. What is the test statistic for this hypothesis test? Give your answer to 4 decimal places.

Answer 1

Solution:

This is a left (One) tailed test,

The null and alternative hypothesis is,  

Ho: 120

Ha: 120

The test statistics,

t =( - )/ (s /n)

= ( 115.79 - 120 ) / ( 57.81 / 35 )

= -0.4308