# Practice Final Summer 2014 KEY

```1) Two possible answers:
Ho: He is poor
Students who said a small alpha needed to
talk about not wanting to pass up a poor man
Students who said a large alpha needed to
talk about not supporting scam artists
Ho: He is a scam artist
Students who said a small alpha needed to
talk about not supporting scam artists
Students who said a large alpha needed to
talk about not wanting to pass up a poor man
2)
DF
Regression 1
Error 48
Total 49
3)
SS
109
1013.914
1122.9
MS
F
109
21.123
5.16
P
.0276
391  391 
1 

391
450  450 
 2.17
 (0.834,0.903)
450
450
4) Ho: It doesn’t matter where you buy your earphones (they all have the same failure rate)
Ha: It does matter where you buy your earphones (some fail faster than others)
α=0.05
The missing expected values are 126.23, 115.41, 13.77, and 12.59
The missing chi-squared values are .361, 2.23
χ23=7.084
0.05 &lt; p-value &lt; 0.10
Fail to Reject
We cannot show any difference in the failure rates among these manufacturers of earphones
5)
If we were testing H0: &micro; = 4000 the p-value would be below 0.02
X
If we were testing Ha: &micro; ≠ 4000 the p-value would be above 0.01
X
If we had sampled only 100 cars the confidence interval would contain the number 4000
X
We are 98% confident the true average mean is between 3221 and 4009
98% of the time a confidence interval like this is done it will contain the number 4000
The true average is between 3221 and 4009 lbs 98% of the time.
6)
59  131  167  275
 158
4
59  1582  131  1582  167  1582  275  1582
4 1
 90
Ho: &micro;≤50
Ha: &micro;&gt;50
α=0.05
t3=(158-50)/(90/sqrt(4)) = 2.4
0.025 &lt; p-value &lt; 0.05
Reject the null
Our data shows that it CAN take more than 50 bullets on average
7)
X
X
?
The evidence shows their averages are all the same
The evidence shows their averages are all different from each other
The evidence does not show there are any averages that are different
The evidence shows at least one average is different from the others
The evidence shows there is someone who is faster than another in this group
The evidence shows there is one person who is faster than all the others
The evidence shows my kids were watching Snow White while I wrote test questions
8) Cannot do
9) 0.01=2.5756*sqrt(p*(1-p)/n)
So n=(2.75/0.01)2*p*(1-p)
Any p is reasonable between 10% (very few freshmen, more students are seniors that can never
graduate) to 25% (one fourth of the options) to nearly 50% (since more students are freshmen,
and then they drop out)
For 10% n=5973
For 25% n=12443
For 33% n=14747
For 50% n=16590
10) (1.32-1.65) &plusmn; 2.201 *0.01/sqrt(12) = (-0.33635, -0.323646)
11) Ho: Server requests are not related to the stock market
Ha: Server requests are related to the stock market
α=0.05
t=.21
p-value=0.837
Fail to Reject
We cannot show a relationship between server requests and the stock market
12)
Super eyes
Ability to fend off wedgies and resistance to getting his lunch
money stolen. He’s a nerd. These powers will definitely come in
handy
The power of confidence
To not be able to finish tests
Ability to predict Ha…. And to fly
I would give him super social anxiety, with an inability to resist
arguments with people both bigger and stronger than him.
I would give him the power of having never ending whiteboard
marker ink
The power to always assume normality
An alpha so large he can reject people out of reality
Probability man – he can predict the likelihood of any event (with
a margin of error of 0.05)
Useful ones like flying and stuff. He can be a statistician as his
alter-ego
X-ray vision (TSA style)
He could change the probability of anything happening to anyone
at anytime
Something similar to the movie “limitless” where he can use more
brain power to super-analyze statistics
Ability to predict the future for only categorical statistics
Ability to do ANOVA in his head
Nothing
```