Quest on Thursday

Last section of the book, aka, Unit VII Review: #10

2-way tables!!

Ch. 26 #12 and 13 (skip part a)

Goodness of fit

Ch. 26 #2 & 8

#6 is even? OK...

#6
69 and 103 > 10

69/172 +/- 1.96*sqrt(.401*.599/172)

I am 95% confident that the true percentage of Adirondack streams that
have a shale substrate is between 32.8% and 47.4%.

a few answers

#8:
histogram looks very nice and normal! (did you draw it?)

7.963 +/- (t*)(8.79/sqrt(27))
t* is for 26 df

I am 95% confident that the true mean difference between boys and
girls who have been drunk at least twice is between 4.5% and 11.4%

#10a)
1772/2000 = 88.6%

b) 250000/304266 = 82.2%

c) Type I = certify the petition when there are not enough sigs.

d) Type II = valid petition not certified.

e) Ho: p = 82.2% Ha: p > 82.2%

1772 and 228 > 10 check!

z = (.886 - .822)/0.008553

Note: use 0.822 in sd formula

z = 7.48, p-value = 0

We reject and say we found sig evidence that the % is greater than
82.%. Certify!

f) To increase power, collect even more sigs. Although it seems like
we have plenty of power.

#16
SRS
2 independent years
260, 240, 270 and 230 are all > 10

(0.54 - 0.52) +/- 1.96*sqrt( (.54*.46/500) + (.52*.48/500) )

I am 95% confident that the change in proportion of students who
choose to enroll is between -4.2% and 8.2%

16b) Since zero is in the interval, we would think that there is not
evidence of a change.

Test coming!

Page 510 and following: #5-10, 13, 16 19, 27
NAME them all.
Do three.

Read page 508

Organize

Today's assignment is to make a 4-quadrant graphic organizer that sorts all the information about the 4 different inference procedures.

Tuesday, March 4th

Ch 24 #8, 12, 23, 24

2-t!

Ch. 24 #7 and 9