Questions: jacobson@cs.uni.edu is my email address.
The Basic Practice of Statistics: Textbook website for David S. Moore's book.
Correlation and Scatterplots - review of the Tuesday class and chapter four formula and Java applet. Regression.
Solution to HW problem 3.44 page 87 of textbook.
3.44 Heights of men and women.
N(64, 2.7) is the height of women ages 20-29.
N(69.3, 2.8) is the height of men ages 20-29.
What percent of young women are taller than the mean height of young men?
In other words, what percent of young women are taller than 69.3 inches?
Young women distribution is N(64, 2.7) so we need to standardiZe 69.3.
69.3 - 64 5.3
z = ------------- = --------- = 1.96 (after rounding it)
2.7 2.7
69.3 - 64 = 5.3
5.3 / 2.7 = 1.96296296296296296296
Look up 1.96 in table A on page 685 of the textbook.
.9750 is the table entry for z = 1.96.
Table entry for z = 1.96 is the area under the standard Normal
curve to the LEFT of z = 1.96, which is the standardiZed 69.3 inches
height, standardiZed to N(64, 2.7).
We need the area to the RIGHT of there, so we subtract the value from
1.0.
1 - .9750 = 0.0250 and that means that 2.5% or 1 woman out of 40
would be taller than 69.3 inches.
It might be just as easy to look up -1.96 in the table and find 0.0250
is the area to the left of that, which is 0.0250.
You can do this if you are comfortable with the idea of SYMMETRY.
The area to the left of -1.96 will ALWAYS be the same as
the area to the right of 1.96 as we discovered in class last week
in a WRT 110 SI session.
What up kid?
You say stat is rough, hurtin your head.
When you got stuck, you should a asked me instead. jacobson@cs.uni.edu
...
Quit flippin.
Talkin about stat is so tough.
Make sure you listen to the lesson while we're telling you stuff.
...
...
but if you wanna get a correct solution
first you must assume a normal distribution. N(0, 1)
equal variance is a needed feature...
... (X - mu) (X - mean)
and we told you to remember this forever z = -------------- = ----------
observed minus mean over standard error sigma standard
dev
...
sometimes two variables in the ranges
one can predict how the other changes
if you got this distinct impression
you're in need of some linear regression
Beta nought is where you cross the y B B
beta one is the slope of the line 0 1
y = a + mx
intercept = a = beta nought = B0
slope = m = beta one = B1
Which model is best,
which is robust
which model leaves the others in the dust
The Basic Practice of Statistics: Textbook website for David S. Moore's book.
HOMEWORK EXERCISES:
Page 87 and 88 - Chapter 3 Exercises
ACT versus SAT test scores problems
Exercise 3.32
Exercise 3.34
Exercise 3.40
Exercise 3.42
These four exercises are due on Tuesday, July 7th
Britney Spears and Carlos Santana HISTOGRAM HOMEWORK assignment.
Pages 59-60 Homework problem 2.34 from Chapter Two Guinea Pig Survival Times Due Tuesday, June 30th...
Wednesday, July 1st Statistics SI session:
How do I get to the Mean and Median applet for our textbook?
Click on the MIDDLE textbook image LINK, the
Basic Practice of Statistics 4E for that page.
-------------------------------
You then will see link to
Statistical Applets
Wednesday, July 1st Statistics SI session: Review for Quiz Two Study Guide.
1. Page 58 - Making Resistance Visible - Exercise 2.26
Making Resistance Visible. In the Mean and Median applet, place
three observations on the line by clicking below it: two close
together near the center of the line, and one somewhat to the
right of these two.
(a) Pull the single rightmost observation to the right. ...
(b) Now drag the single rightmost point to the left as far as you
can. ...
(See your textbook, page 59 for the rest of (a) ... and (b) ...)
2. Page 59 Exercise 2.32
Behavior of the median. Place five observations on the line
in the Mean and Median applet by clicking below it.
(a) Add one ...
...
Where is your new point?
(b) Use the applet to convince yourself that ...
...
Explain why this must be true.
http://www.whfreeman.com/bps/
3. Here is a set of 12 numbers. How fast can you answer the following
questions? Can you do it without looking at your notes or your
textbook?
1 2 3 4 5 6 7 8 9 10 11 12
--- --- --- --- --- --- --- --- --- --- --- ----
12 100 150 180 200 220 250 300 330 350 400 1000
is a data set with n = 12 which would be good practice for doing the
5 number summary.
i. Give the 5 number summary. Show your work when needed so it
can easily be seen what numbers you were using to get the
Median or Q1 or Q3, in case of arithmetic errors.
102 + 109
Example ------------- = 105.5 = Q1
2
ii. What is IQR?
iii. Are there any outliers in the data?
iv. What is the lower cutoff point or value for outliers, i.e.
what is the value lowCutOff in the following?
lowCutOff <= non-outlier values <= highCutOff
v. What is the upper cutoff point or value for determining
outliers, i.e. what is the value highCutOff in the following?
vi. Draw the boxplot for your 5 number summary.
4. Go over the quiz one questions that you missed and make sure you
understand why you missed the question. Categorical and
Quantitative, Stem Plots, Histograms, etc.