Thursday, June 14, 2007

Statistics

Our class ages (the data we will use as an example): 16, 15, 15, 15, 16, 16, 16, 16, 16, 15, 16, 16
This is a data set. It has some characteristics, we can use technology to learn some things about the data set.

For Instance:
1. Median (average)
"add all the numbers then devide by the number of numbers" ; )





2. Measures of Central Tendency
a) Median
The middle number, provided they are arranged numerically, and is odd (if n is even then the median is the mean of the two middle numbers).
b) Mode
"The most frequently appearing value." * There can be multiple modes or no modes.*

3. Range
The distance (in numbers) from the smallest to largest or vice versa (always positive).


How to get this information on you ti 83/84 calculator:

I. Clear your stat plots or be sure to use the correct plot when inserting you information (I'm using the information from the example at the begining of the post).
II. Go to "STAT" then "1: Edit..." and insert your list.
III. Go to "STAT", "CALC" then "1: 1-Var Stats".
IV.Now enter you list number (L1, L2, etc.). If your using our (class) example you should have first cleared all your lists and now on your home view (with 1-Var Stats on it) you will push "2nd, 1" to enter L1. "ENTER"

Wednesday, June 6, 2007

Vertical Line Test

Vertical Line Test

If a vertical line can be drawn to intersect more than exactly one point on a relation then that relation cannot be a function because it fails the vertical line test.

Relations and Functions

Relation is any set of ordered pairs.

ex) {(2,6),(-7,7),(4,3),(-7,2)}

X 0 1 2 3 4 5 6
Y 0 1 2 3 4 5 6

X--------M
Y--------N
Z--------O


y=2x+5
"the set of ordered pairs such that y is twice x"

all of these relations are functions except one. The first one isn't a function because it fails the vertical line test.