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Email: jean.linner@cobbk12.org
Extra help is available before and after school. See you at CiCi's!
Lassiter High School
2601 Shallowford Road
Marietta, GA 30066
770-494-7863
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About Me
- Mrs.L
- AP Statistics info for Lassiter students and our friends. Email and webmaster:jean.linner@cobbk12.org
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7 comments:
So, what are the important topics of this chapter? What should a successful student be able to do?
Am I the only one reading this?
Do you know how to write a probability expression? I'll use "LT" for the less than sign because the HTML won't accept the sign. For instance, if you wanted the probability that X was greater than 5 and less than 11, you would write
P(5 LT X LT 11)
and, of course, you would shade that area on the density curve. If the distribution was normally distributed with a mean of 7 and a standard deviation of 2
[X~N(7,2)], then the probability expression is equivalent to
P((5-7)/2 LT Z LT(11-7)/2), which is also P(-1 LT Z LT 2). Hey! That's a probability that you can look up using the calculator or your tables!
Make good use of your time. Remember, I am not trying to test your geometry or algebra, but don't let crummy math skills get in the way of showing me your best statistics work on the test.
Wow! That comment disappeared fast. The author said that y'all need to know the Empirical rule! True.
I added a link on the edge of this page for the online quizzes. Have fun!
R^2 represents the portion of the variation in the y values that could have been predicted using your linear model. The rest of the variation is just randomness. Think of all the other lurking variables which also have an effect on y. Therefore, if r^2 = 36%, . . . [can you interpret the rest?]
Does the model work well? Would you feel comfortable relying on it?
Mrs. L
. . .36% of the VARIATION.
I wouldn't be too happy, either.
TWYMFS.
Mrs. L
Our residuals should be scattered. If the residuals have some other pattern, then we could generate a better model using a quadratic or higher-power equation.
Re: the Y2 equation
You are comparing the residuals to zero. The x-axis should show up without plugging in the equation if you have your calculator set for axes on. You will always have some values above the axis and some below. The common mistake is that people think that an even distribution above and below guarantees a good fit. Not true. Again, the residuals should be scattered, without a clear pattern.
Of course, TWYMEFS.:)
Mrs. L
Welcome, Mary. I hope that your studying is going well.
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