a trend line or a You can study the line to see how the data behaves You may have a basis predict what the data might be for values not given line of best fit Line of Best Fit ID: 628780
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Slide1
Line of Best FitSlide2
Sometimes points on a scatter plot are represented by
a
trend line or a ___________________. You can study the line to see how the data behaves. You may have a basis predict what the data might be for values not given.
line of best fitSlide3
Line of Best Fit
Line of Best Fit is a
line that approximates a trend for the data in a scatter plot. It shows pattern and directionSlide4
Line of Best Fit
a line that approximates a trend for the data in a scatter plot
shows pattern and directionSlide5
How to Find the Line of Best Fit
The line of best fit should:
pass through as many points as possibleallow remaining points to be grouped equally above and below the lineSlide6
Draw the line of best fit for the following scatter plots:Slide7
Draw the line of best fit for the following scatter plots:Slide8Slide9Slide10
Why make a Line of Best Fit?
Helps us to make predictions by
INTERPOLATING EXTRAPOLATINGSlide11
Interpolating:
Estimating a value
BETWEEN two measurements in a set of dataExtrapolating: Estimating a value BEYOND the range of a set of dataHelps us determine if it is a weak or strong correlation. Slide12
Interpolating
– what would the wife’s age be of a husband who is 57?
Extrapolating
- what would the wife’s age be of a husband who is 84?Slide13
If the data points are close to the line of best fit, it is said to have a ___________correlation.
strong
weak positive
weak negative
strong negative
strong positiveSlide14
Use the line of best fit to predict how many tornadoes may be reported in the United States in
2015
if the trend continues.
1950
1955
1960
1965
1970
1975
1980
1990
1985
1995
200
400
600
800
1000
1200
2000
2005
2010
2015
If the trend continues we predict that there will be 1200 tornadoes reported in 2015.Slide15
Finding the Line of
BEST
FitUsually there is no single line that passes through all the data point, so you try to find the line that best fits the data. Step 1: using a ruler, place it on the graph to find where the edge of the ruler touches the most points. Step 2: Draw in the line. Make sure it touches at least 2 points.Slide16
Finding the Line of
BEST
Fit (continued)Step 3: Find the slope between two pointsStep 4: Substitute that into slope-intercept form of an equation and solve for “b.”Step 5: Write the equation of the line in slope-intercept form.Slide17
Let’s try one:
SANDWICH
Total Fat (g)Total CaloriesGrilled Chicken 5300Hamburger9260Cheeseburger13
320
Quarter Pounder
21
420
Quarter Pounder with Cheese
30
530
Big Mac
31
560
Arch Sandwich Special
31
550
Arch Special with Bacon
34
590
Crispy Chicken
25
500
Fish Fillet
28
560
Grilled
Chicken with Cheese
20
440