Question
A random sample of 22 students weights is drawn from student population.

Investigate whether the average weight of student population is different from 140 lb.

135 119 106 135 180 108 128 160 143 175 170

205 195 185 182 150 175 190 180 195 220 235

a) State the null and alternative hypothesis (Hoand Ha).

b) What are the n, , s?

c) Compute the t-statistic. What is the degree of freedom (df)?

d) Find P-value from the table-D.

e) Find P-value from the following website. Compare with what you get from d).

http://surfstat.anu.edu.au/surfstat-home/tables/t.php

f) Test the hypothesis at the significance level ?=0.05. Reject Ho or Ha? Why?

g) What conclusion can you make about the mean weight of students?

Construct 95% Confidence Interval for the students mean weight.

h) What value for t* should you use? Find the t* value from table-D and the website above.

i) Do the calculation for the 95% Confidence Interval.

j) Based on the 95% Confidence Interval from i), what conclusion can you make about the hypothesis in a)? Why?