Section 2-5 Continued

Scatter Plots

And

Correlation

Def: A scatter plot shows the relationship between a collection of ordered pairs.

Enter your lists of data

Steps on Calculator

Stat then Enter(you will see lists)

Enter data by entering x-values in L1 and y-values in L2

To clear data

Steps on Calculatory = clear all equations

Stat then Edit( you will see lists)

move curser to L1

Clearmove curser to L2

Clear

To make a scatter plot using yourcalculator use the following steps:

h s1 601 552 682 702 1003 653 703 803 743 684 704 804 885 925 756 856 946 1006 987 95

1.

Enter this table into yourcalculator and make a plot.

Where h = hours studied (x) s = test score (y)

List 1 List 2

To make the plot

Steps on Calculator

2nd Stat Plot(select Plot 1) by keying Enter

(you will now see the menu for making a plot)Move curser over the desired menu selections

below and key enter after each choice

On OffType (first choice)

X List (select L1 or enter list name)

Y List (select L2 or enter list name)Mark (first choice)

To graph

Steps on Calculator

2nd Quit(returns you to the main screen) Window adjust window to fit the data

(key Enter after each entry)

Xmin= -10Xmax= 100Xscl= 1 Ymin= -10Ymax= 120Yscl= 1

Now key GRAPH

2. Find the line of “best fit” The calculator steps are:

STAT

CALC

4:LinReg(ax+b) Enter,

,

,

Your home screen will say: LinReg(ax + b)

Enter

The calculator will calculate the answer:

y = ax + bWhere

b = y-intercept

a = slopea = 5.643791

b = 57.90359

Line of best fit

y = (5.643791)x + 57.90359

3. Enter the equation of best fit into your calculator

y = (5.643791)x + 57.90359

Does the line look like a reasonableapproximation of the data?

Def: The process your calculator goes throughTo find the line of best-fit is called aregression analysis

Homework

Page102 # 1,2 and 3

•Use you calculator to draw a scatter plot

•Use your graphing calculator to find the equation for line of best-fit (write the equation in y= mx +b form on your homework).

•Answer analysis questions