# ANOVA chapter..... 2 problems , one anwered - did I do it correctly? one no clue

• Oct 3rd 2012, 06:18 PM
cama62
ANOVA chapter..... 2 problems , one anwered - did I do it correctly? one no clue
I actually have two problems - the first I have attempted to figure out, but not sure I have it correcct. Still don't understand how to interpret the answer I get.

A Stockbrocker at Critical Securities reported that the mean rate of return on a sample of 10 oil stocks was 12.6 percent with a satnadard deviation of 3.9 percent. The mean rate of return on a sample of 8 utility stocks was 10.9 percent with a standard deviation of 3.5 percent. At the .05 significance level, can we conclude that there is more variation in the oil stocks?

I have F=3.9^/3.5^ =1.2416
n1 - 1, n2 - 1 = 9,7
Critical F value =3.667
Reject if F 3.667 ???
1.2416 < 3.667 so fail to reject?

Did I calculate correctly - and how does that result translate to answer is there more variation?

This next problem - need help on set up and interpretation.

The following is sample information. Test the hypothesis at the .05 significance level that the treatment means are equal.

Treatment 1
9,7,11,9,12,10

Treatment 2
13,20,14,13,

Treatment 3
10,9,15,14,15,

a.State the null hypothesis and the alternate hypotheses.
b.What is the decision rule?
c.Compute SST, SSE, and SS total.
d.Complete an ANOVA table.
e.State your decision regarding the null hypothesis.
• Oct 3rd 2012, 07:00 PM
pickslides
Re: ANOVA chapter..... 2 problems , one anwered - did I do it correctly? one no clue
Quote:

Originally Posted by cama62
I have F=3.9^/3.5^ =1.2416
n1 - 1, n2 - 1 = 9,7
Critical F value =3.667
Reject if F 3.667 ???
1.2416 < 3.667 so fail to reject?

Yes, if your calculated F-value is less than your critical F-value then fail to reject the null hypothesis.
• Oct 3rd 2012, 07:05 PM
MaxJasper
Re: ANOVA chapter..... 2 problems , one anwered - did I do it correctly? one no clue
http://mathhelpforum.com/attachment....1&d=1349319905
T1<>T2 (p<0.05)
T1=T3 (p>0.05)
T2=T3 (p>0.05)
• Oct 3rd 2012, 07:16 PM
MaxJasper
Re: ANOVA chapter..... 2 problems , one anwered - did I do it correctly? one no clue
$P_f\left[\frac{3.9^2}{3.5^2}|\nu _1=9,\nu _2=7\right]=0.60356>.05$ Can't reject equal variance hypothesis.