Day 25:
Heart of Mathematics
Last time
: Embarrassing questions
Next time
: Section 8.3: Money Matters
Today:
Final project paper were due next Monday, 4/21; let's extend that to Wednesday, 4/23.
Visit the
writing center!
Look for, find, and illustrate the
mathematics
.
The Schedule
of presentations.
Important:
You need to be there for your classmates.
If you are not in class for the other presentations, you will lose points on your own.
Section 6.3 mindscapes due today
Last time: Section 7.5: Collecting Data rather than dust (the power and pitfalls of statistics)
Assignment: Mindscapes pp. 581-: #1, 3, 4, 8; Type up 12.
due Monday, 4/21
Sampling with randomness
Let's calculate the true rates of maleness and femaleness in class...
Each person will flip a coin:
If it's heads, answer "Male"
(this should be the "embarrassing answer", to provide cover)
If it's tails, answer truthfully.
How do we now estimate the true rate?
Guess that half the "Male" answers are from heads; the other half are truthful answers.
How could we adapt this process to lose less of our data?
How would we choose an appropriate level of "data-loss", and "answer-protection"?
Now: what embarrassing question should we now attempt to answer? Who's got something they really want to know?
Section 7.6: What the Average American Has
(or had, in 1993)
Mindscapes #5, 6, 9, 23, 26 (type up #22)
Due Wednesday, 4/23
Some statistics:
The average American has one testical and one ovary.
The average income for a Lakeside School graduate was $2.5 million
(in 1997)
What's in a mean?
Let's try a different measure of "central tendency":
The median American has no testicals and two ovaries.
What's in a measure of center?
Visual display of data:
What's not in a mean or median? Spread, or
variation
Heights of our class
Heights of people tend to be normally distributed
(if distinguished by sex); otherwise, if the sexes are combined, you might expect a
bi-modal distribution
Normal distributions arise quite naturally (hexstat)
Cars
How do we quantify variation?
"The mean difference from the mean" is one way....
Standard deviation is another. This of this as a "typical deviation" from the mean, or a "standard deviation"...
In any event, these measures help us to appreciate about by how much an individual measurement typically varies from the mean.
Some other innovative, ingenious, imaginative visual displays of data
Website maintained by
Andy Long
. Comments appreciated.