Question

A paleontologist examines 39 skeletons of a new species of dinosaur and finds that the average length of the right femur is 90 cm, with a standard deviation of 9 cm.
a. Does this involve ?-values or ?-values? Explain how you know this.


b. Estimate the population mean with 95% confidence.

Answer 1

Solution: Here the given information are

sample=n=39

sample mean ==90

sample standard deviation=s=9

a) In this example involve t-values.

1) We don't know the population standard deviation. So we use the t-values.

2) In this example paleontologist examines 39 skeletons of a new species of dinosaur and find mean and standard deviation. That means one sample t test example.

b) Estimate the population mean with 95% confidence.

Significance level==0.05

degrees of freedom=n-1=39-1=38

t critical value== = =2.02------(from t table nearest degreees of freedom)

C. I. =

=

=(90-2.02*1.44, 90+2.02*1.44)

=(90-2.92, 90.+2.92)

=(87.08, 92.92)

Estimated population mean with 95% confidence is (87.08, 92.92)