Question

A recent study compared different psychological therapies for teenage girls suffering from anorexia, an eating disorder disease. In the study of 18 girls the average weight gain is 5 lbs with sample standard deviation 7.32. In order to test the hypothesis that the girls weight gain is greater than 3.5 lbs. Find the critical value (use t table) when alpha=5%.

Answer 1

Solution :

= 3.5

= 5

s = 7.32

n = 18

This is the right tailed test .

The null and alternative hypothesis is

H0 :   = 3.5

Ha : > 3.5

= 0.05  

The two tailed test critical value is tc = 1.740

Test statistic = t

= ( - ) / s / n

= (5 - 3.5) /7.32 / 18

= 1.043

p(t >1.043 ) = 1-P (t< 1.043 ) = 0.1558

P-value = 0.1558

= 0.05  

0.1558 > 0.05

Fail to reject the null hypothesis .

There is not sufficient evidence to suggest that