1) Z=(9.98-10)/(0.03/sqrt(3) = -1.15

2) (16.5-25.7)+-2.39*sqrt(41.785/36+41.785/36) = ( -12.84, -5.56)

3) Cannot do not normal

4)

DF / SS / MS / F
Groups / 2 / 8.6402 / 4.321 / 24.108
Error / 9 / 1.6128 / 1792
Total / 11 / 10.253

5) .02/2=1.282*sqrt(.3(1-.3)/n)

N=3451.4

Need 3452 emails

6)

H0: Hair color and eye color are independent

Ha: Hair color and eye color are dependent

Exp / Brown / Blue / Green
2 Hours / 22.1 / 19.1 / 17.7
5 Hours / 24 / 20.8 / 19.2
7 Hours / 28.8 / 25.0 / 23.1
Partial
Chi^2 / Brown / Blue / Green
2 Hours / 0.37 / 0.07 / 0.16
5 Hours / 1.042 / 1.62 / 0.03
7 Hours / 2.15 / 1.94 / 0.03

χ24 = 7.412

.1 < P-value < .15

Therefore Fail to Reject the null

Which means there is not sufficient evidence to prove that beam color and fire resistance are dependent

7) 0.02<p-value<0.04

8)

H0: proportions are equal (not cheating)

Ha: proportions are not equal (is cheating)

Alpha = 0.05

18 / 20
14 / 30
14.83 / 23.17
17.17 / 23.83
0.678 / 0.434
0.5852 / 0.3747

X21=2.072

p-value = 0.0749

0.10<p-value<0.15

Fail to Reject

We cannot say my daughter is cheating

9) (14-15) +- 2.998*1.22/sqrt(8) = (-2.29, 0.293)

10)

H0: B1=0

Ha: B1≠0

α=0.05

t5=-1.02/0.246 = -4.15

2*.0025<p-value<2*0.005

0.005<p-value<0.01

Reject

Heavier cars do not carry the same amount of Freon

11)

H0: mu >=2

Ha: mu < 2

Type 1 error: The batteries will last, but we think they will die (lose money)

Type 2 error: The batteries will not last, but we think they will (no calculator during test)

Personally I would raise alpha, maybe 0.20 because I don’t want my calculator to die during the exam, and this would make it more likely that I am going to replace them (even if I don’t need to)

12)

______95% of the time confidence intervals like this capture the true average time between a felony

______We are 95% confident the true average is between 2.3 and 5.7 seconds

13)

H0:μ≤1

Ha:μ>1

α=0.05

Note that “Error” refers to how far off from 2

0.025<p-value<0.05

Reject the null

The average error from the scale is significantly more than 1, which means the scale needs to be replaced

14)

9 said do the homework

7 said enjoy the songs

5 said take good notes

4 said study with classmates

4 said don’t use the book

3 said attend class

2 said go back over the homework

2 said get help when you need it

2 said start the homework early

Other responses:

Put confidence intervals on your study sheet

Learn the language of statistics

Pay attention to the wording and context of the questions

Make a flow chart

Go to office hours

Make a good study sheet for the exam

Study hard

Pay attention in class

It’s not that hard

Do the practice exams

Don’t do the homework all on one day

Don’t work 30 hours and take 15 credits

Use engineering paper

Beware the final!

Don’t forget everything on the final

Everyone hates statistics. Just do better than the next guy and get it over with

You’ll never get an A in this class

Run! The instructor is insane and possibly dangerous. Quit this silliness and join the college of business

Dr. Crawford is a thug and he don’t take no crap. Don’t give him crap.

Good luck roll Tide

Statistics is like a garden. Dig it