Question

AP STATS HELP!! REWARD WITH MEDAL, FAN, and TESTIMONY!!
b. Based on this sample, does a person's opinion on gun control depend on party affiliation, at the .05 level of significance?

Answer 1

@superdavesuper @amistre64 @kropot72 The information you need is in the attached picture.

Answer 2

sorry I don't understand the difference between "expected" and "observed" as stated in ur prob. so I cant help :(

Answer 3

its a chi squared lesson that involves expected values

Answer 4

Ahh no wonder I looked again n still couldn't understand. I did not take that class. Plz see if u can get someone else to help u.

Answer 5

will do :) thank you for trying though

Answer 6

@sdfgsdfgs

Answer 7

yes? no luck in gettin' other helps? :(

Answer 8

nope

Answer 9

there are some helpers online....u may want to tag 'em n see if they will help

Answer 10

@nincompoop

Answer 11

@jtvatsim got anything??

Answer 12

I'm a little rusty, give me a sec... I think I can get something... :)

Answer 13

To clarify, did you get anything for part A? What were your expected values?

Answer 14

yes.

Answer 15

Democrat favor: 16.72
Democrat Oppose: 23.04
Democrat Unsure: 2.52

Republican favor: 12.16
Republican oppose: 23.04
Republican Unsure: 1.4

Answer 16

OK, thanks. Your results are a bit different than mine: How did you compute your expected values? Did you use a formula?

Answer 17

yes.

Answer 18

look at democrat favor:
44*76/200 = 16.72

Answer 19

love the screen shot name... lol

Answer 20

lol I was attempting creativity, plus I am running low on names lol

Answer 21

OK, I understand what you did with the formula.

Answer 22

I need help with b

Answer 23

Alright, still working on it... :)

Answer 24

I'm just a bit concerned that those expected values don't add up to the correct totals.

Answer 25

thank you very much you are a life saver

Answer 26

No worries. :)

Answer 27

OK, since this is the chi^2 test, we will use the following formula...

Answer 28

(correct me if I'm wrong)

x^2 = sum of (observed frequency - expected frequency)^2 / expected frequency

\[\chi^2 = \Sigma \frac{(f_o - f_e)^2}{f_e}\]

Answer 29

That is we compare each observed frequency to each expected frequency according to the formula and sum up.

Answer 30

We will have six calculations (one for each category). Does that make sense so far?

Answer 31

yes sir/mam

Answer 32

What should I call you?

Answer 33

sir will work :)

Answer 34

ok :)

Answer 35

Though I am just a recent graduate from university :)

Answer 36

NICE!!! Did you like it? What was your major?

Answer 37

sorry, off topic, ADHD.... that happens some times

Answer 38

No worries, I have a couple of friends that have ADHD. As far as the degree, I did enjoy it, but don't be scared... it was mathematics major :)

Answer 39

nice! You plan on teaching?

Answer 40

Yes, actually I do. :)

Answer 41

I want to rebel against the traditional way of teaching math, which is really bad and confusing.

Answer 42

I am graduating next month and I plan on doing a double major in History and English and then teaching....

Answer 43

me too... but with History... I want to make it fun to learn

Answer 44

That's awesome! We certainly need more knowledge of history and english. That's impressive that you did a double major.

Answer 45

:) It's impressive that you graduated with a diploma in Mathematics... That is something I could NEVER do...

Answer 46

Haha! You might be surprised what you can do with enough time, frustration, and patience. But, sometimes it is nice to just do what you like (which luckily for me was math) :)

Answer 47

yeah

Answer 48

ANYWAYS MATH!!

Answer 49

OK, I've computed the values, and I am pretty confident that this should be what the values of the expected outcomes are:

Answer 50

That might mess you up for part A... but the formula I used was (bottom subtotal/grandtotal)*(right subtotal). For example, Democrat Favor is (76/200)*110 = 41.8.

Answer 51

hmmmm ok.

Answer 52

In any case, the thing that bothers me about the formula you applied was that you get results in which the Democrat total should be 110, but you expect 16.72 + 23.04 + 2.52 = 42.28 which isn't consistent.

Answer 53

I am confident in the numbers I have computed (I'm rewatching the video lessons I took for Statistics as we speak), so I will do the chi^2 computation with those numbers.

Answer 54

chi^2 = (44-41.8)^2/(41.8) + (48 - 52.8)^2/(52.8) + ...
= 2.20

Answer 55

I left some steps out to save space, but do you follow?

Answer 56

yes

Answer 57

Great! We have chi^2 = 2.20. Alright, now we need to look up our result in a chi-squared table or use a calculator. Either way, we must also know what our "degrees of freedom", df, are which is just "the number of categories minus one". In our case, we have three categories (Favor, Opposed, Unsure), so df = 2. OK so far?

Answer 58

I'm using this table: https://people.richland.edu/james/lecture/m170/tbl-chi.html

Answer 59

ok

Answer 60

sorry I am taking notes as we go along

Answer 61

That's totally fine. :)

Answer 62

Then, using either table or calculator, we find that a value of chi^2 = 2.20 and df = 2 has a probability somewhere between p = 0.90 and p = 0.10. This is not significant at the p = 0.05 level. It should be less than p = 0.05.

Answer 63

If you want a MUCH more clear explanation with supporting graphics, you should check out Udacity.com. They have a free statistics video course and lesson on chi^2 tests.

Answer 64

ok

Answer 65

so that is how I will find my 0.5 level of significance

Answer 66

That is correct. Everything is by tables or calculator.

Answer 67

Thank you very much!! You are a life saver!!

Answer 68

Here's the exact course I used: https://www.udacity.com/course/intro-to-inferential-statistics--ud201

Answer 69

Your welcome! Glad to help!

Answer 70

I believe it is lesson 16 if I'm not mistaken.

Answer 71

I will take a look at it... Thank you

Answer 72

Your welcome! Good luck with the AP work!