Many of you are wondering ...
"What exactly is AP Statistics???"
"Statistics" is the Science of Data. This data comes in different forms:
lists, tables, charts, graphs, words.
In previous math courses you were provided some introductory statistics concepts
like linear regression, box-whisker plots in Algebra 2, mean, median, and
mode in middle school, graph reading using pie charts and bar graphs among
others. During the 04-05 school year my algebra 2 students compared
box-whisker plots for the grade averages amongst the three sections of Honors
Algebra.
This course goes way beyond just entering data (mucho data) and drawing
pictures. Statistical analysis, gathering data through experiments or
surveys, describing the data, forming conclusions, and making predictions
are really what statistics is all about. We'll use a few familiar words
like mean, median, and probability and learn lots of new concepts with "freaky
formulas". We often will want to make statements or predictions about an
entire population of individuals.
Sometimes, most times, the population is too large to study directly. If
we desire to find the approximate mean (average) age of the residents of
Georgia, it would be too costly to visit each person. So...we take
samples. Specifically, random samples that contain manageable
amounts of data. Each sample has its own mean and we need to take many,
many samples because only then will the mean of the means "approach" the mean of
the population. Are you getting all this???
Randomness is an important part of data gathering - how we use random events is frequently done through simulation, a pretend experiment. Probability and its many rules will play an important part eventually.
Looking at graphs of data, giving numerical descriptions,
drawing conclusions all lead to the "ultimate" - making decisions and/or
predictions about not only other samples but even the entire population.
Of course our predictions will only be as good as our data and our "methods".
We will never be 100% sure, but hopefully we can be somewhat confident.
Statistical INFERENCE is the process of "inferring" information beyond the scope
of the actual data with some attempt at accuracy. Back to the mean age of
all residents of Georgia. I say 52 - this is just a guess and I am not at
all confident...maybe too high, maybe too low. There are procedures for
determining confidence intervals from which we can say we are very confident
about our conclusion. The typical confidence intervals are 98, 95, and
90%. Any less confidence than that and the conclusion is not very
reliable.
Let's get a little more specific with some terminology.