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We studied measures of center, shape and spread, I had a lot of new terms spinning around in my
head.
We found median and mean and something new…..An extreme
value caused a skew, An extreme value caused a skew.
“A” plus “BX” will change medians and means Because they measure central tendancy But that “A” won’t
mess with the standard dev.To change the spread just multiply by “B”, To change the spread just
multiply by “B”
Probability was a mystery, until we learned about dependency. I’d use
a tree diagram if it was really tough, or a venn diagram if that
wasn’t enough.
Then the law of large numbers made it clear to me That inference
is based on probability That inference is based on
probability
Remember the conditions for normalcy Are N times P, and N
times one minus PIf they’re not bigger than the
number ten, We need a bigger sample to try again, We need a
bigger sample to try again
Making an inference with legitimacy, Requires SRS and
checks for normalcy We like the t-distribution when sigma’s unknown, Its degrees of freedom are N minus
one. I’ll write out what the AP readers need to see But I’ll check
my calculations on the 83,I’ll check my calculations on the 83
I’ll articulate conclusions from the value of T, Or compare the values
of alpha and P Remember the procedures for using T, It really doesn’t matter if N is more than
forty, It really doesn’t matter if N is more than forty
Designing an experiment is really the key To getting some results
with validity We assign a treatment group with randomization
A block design will help reduce the variation
Undercoverage, non-response, and poorly worded questions Are forms of bias that require our attention Forms of bias that require our
attention
So remember correlation is not causation For the latter we need experimentation Also r-squared is percent of variation Explained by
the least squares regression equation, Explained by the least
squares regression equation