Heard in passing today:
Hang up. Log off. Study.
OK, if you log off you can't blog with the APSTAT crowd.
*** What are the most important concepts from each chapter?
*** What are the parts that you still don't understand?
HW: Write down the three most important from each chapter, 1-7. Due Monday.
*** CiCi's on Sunday.
*** Review sessions Monday 8-9PM for 5th and 6th periods, Tuesday 8-9 PM for 1st and 7th periods.
*** I have a meeting Monday morning. I will get to the MU as soon as possible.
*** Yes, we are having classes in 1st and 7th periods on Tuesday!
Post away, my statty friends.
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9 comments:
A question was raised:
How do you generate the list of possible outcomes when flipping coins, having boys/girls, etc.?
Use binary!!!
Our goal is to enumerate the 2^3 = 8 ways that three coins flipped could come out.
Count in base 2 and fill in the spaces with zeroes. On the left is the number, on the right is the number written in binary.
0: 0 0 0
1: 0 0 1
2: 0 1 0
3: 0 1 1
4: 1 0 0
5: 1 0 1
6: 1 1 0
7: 1 1 1
Now, let the ones represent tails or girls or red or successes of some other type. The zeroes will be the other outcome.
1 H H H
2 H H T
3 H T H
4 H T T
5 T H H
6 T H T
7 T T H
8 T T T
Ta DA! You have enumerated the 8 different ways the events could happen.
How many questions? Enough to keep you busy for 70 minutes. Probably 35-40 MC.
Straightening curves? If it looks like an exponential curve, decaying or growing from a point on the y-axis, take the log of the y values. If it looks like it grows from the origin, it is probably a power curve: take logs of both x and y. THEN, if he straightened data look better, find the LSRL through that set, check the residuals, and convert the LSRL equation into a curve by replacing x and/or y with the REAL name of the thing you used (log x? log y?).
Let's see. On a multiple choice test, how could the teacher make sure that a student knew how to find the equation of the curve through a set like this???
Anyone?
You want P(X > 700).
That's the same as
P((x-mu)/sigma) > (700-530)/120)
which is where we converted the value 700 into a standardized form: the number of standard deviations above (or if negative, below) the mean it is.
700 is 1.416667 standard deviations above the mean.
Use the Z table or your calculator (normalcdf) to find the area under the normal curve to the right of 1.416667.
Thanks for asking!
Least squares regression problem:
Suppose that your data have been straightened by taking the log of y and graphing that against x. The straightened data resulted in a LSRL on the calculator of Y-hat = 0.5 + 1.5X. What is the equation of the corresponding curve that passes through the original data?
For these density curves, the probability is the area below the curve (which could actually be a straight line)down to the x-axis. This means that a circle with area = 1 sitting on the x-axis could NOT be a valid density function.
6th Period Notes
ch 5: experiment proves causation.
causation is proved when a response is lost once the stimulant is removed.
3 parts of good experiment: 1)repition 2)randomness 3)control.
stratification nor blocking are necessary parts of the experiment--have to do with experimental design.
SRS has specific characteristics
1)cluster
2)stratified
3)systematic
chapter 1:
displaying distribution with graphs and numbers
SHAPE, CENTER, SPREAD, UNUSUAL OBSERVATIONS
measures of center: mean, median, mode (median and mode resistant to outliers)
measures of spread: standard deviation/variance, range, interquartile range
*interquartile range not affected by outliers
Chapter 2:
68-95-99.7 rule (1-2-3 standard deviations from the mean in each direction).
z less than or equal to -3 or
z greater than or equal to 3 is REALLY GOOD!!
Remember the Normalcdf!
Work with the logistics of symmetry when finding z values.
Chapter 4:
r^2: coefficient in variation
r: correlation coefficient
b=r times standard deviation y/standard deviation x
use log or ln of y-hat when straightening data.
can use logy, logx, or logx logy
Chapter 6:
tree diagrams - branches are conditional probabilities. must be multiplied out.
Venn diagrams--be careful with the percentages of combined events
study!! bring a calculator!! good luck!!
LOVE the icon!
Don't worry! You do not have to use normalpdf in AP Stat.
Remember when we talked about density functions, like the uniform density function which looks like a rectangle or a triangular density function? We identified the equation of the "curve" that formed the top edge of the region we used for probability calculations. It looked like y=1 or y=0.5x or something simple like that. Like that, normalpdf is the function that actually forms the bell-curve for normal distributions. If you wanted to draw the curve using a formula, you could use that function with the mean and standard deviation identified.
In this class you can just ask the 2nd Dist Draw function on your calculator to sketch the desired graph.
Good luck, everybody.
when your trying to graph residuals, using your calculator, what formula do you put in to get the residuals?? is it L2-Y1(L1)???
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