Statistic Decision Making Final Exam

Exercise 2: Sample Design and Evaluation The information can be summarized as follows:
N1= N2
Standard Deviation= 15
Difference in Performance= 5
Power= .8
After entering the given information, the window looks as follows, which shows us that
N1= N2= 142

In the window above, change the power to .9, then N1= N2 = 190

In the window above, change the sigma1=15, sigma2=12, and don’t select Egual Sigmas checkbox, thus I get N1= N2= 156 In the window above, change the N1=200 (control group), N2=120 (testing group), and select Independent in Allocation, thus I get .9046 to be the power.

=((61-64.5)-(0))/√((16*16)/200+(13*13)/120) = (-3.5)/1.6396 = -2.1347
Critical Value: Zα/2= Z0.05/2= @qnorm(1-0.05/2)= 1.96
When comparing the test statistic to the critical value: Z=2.1347>1.96, we reject the null hypothesis.
We can calculate the P-value using the EViews command:
Show @tdist (t, d.f)
In this EViews command, t stands for the appropriate test statistic and d.f are the degrees of freedom. The appropriate test statistic was calculated above, namely Z=2.1347. For the degrees of freedom, we can insert NA+NB-2.
Show @tdist (2.1347, 318)= 0.03355
Since the P-value= 0.033550, and β1= 0.86361050000 ls price c assessval
Dependent Variable: PRICE
Method: Least Squares
Date: 01/21/13 Time: 16:07
Sample: 1 650 IF PRICE>50000
Included observations: 562

Variable Coefficient Std. Error t-Statistic Prob.

C 12314.91 3021.988 4.075103 0.0001
ASSESSVAL 0.823041 0.022695 36.26546 0.0000

R-squared 0.701363 Mean dependent var 113069.1
Adjusted R-squared 0.700829 S.D. dependent var 51534.97
S.E. of regression 28187.83 Akaike info criterion 23.33472
Sum squared resid 4.45E+11 Schwarz criterion 23.35013
Log likelihood -6555.056 Hannan-Quinn criter. 23.34074
F-statistic 1315.184 Durbin-Watson stat 1.337129
Prob(F-statistic) 0.000000

Estimated