MTH 125
Lab 8
Regression/Correlation Name_______________________________ In Mark Twain’s book Life on the Mississippi, he made a strange prediction about the
future of the Mississippi River. The river is extremely crooked with many curves. From
time-to-time “cut-offs” take place in which the river changes its course from a wide bend
to a straighter path. As a result the length of the Mississippi is getting shorter. Twain
gave some figures: “The Mississippi between Cairo (Illinois) and New Orleans was 1215
miles long 176 years ago. It was 1180 miles after the cut-off of 1722…..its length is only
973 miles at present (1875). Any calm person who is not blind or idiotic can see that 710
years from now the lower Mississippi will only be about 2 miles long.”
1. Graph the points given and calculate the linear regression equation for these data. 2. What’s wrong with the reasoning? 3. Give an example of a similar jump to conclusions. Lab5 Page 1 of 5 4. The table represents the average blue book value for a Honda Civic LX bought in
2003 for $15,000. The number zero represents the purchase year (2003) and the
numbers 1 – 6 represent the years since purchase.
Year
Value 0
$15,000 1
$13,200 2
$12,075 3
$11,050 4
$9500 5
$7900 6
$7100 a. Make a scatter plot of you data as a check for linearity and outliers. b. Guess a reasonable correlation coefficient for your scatter plot. c. Find the equation of the regression line for your data. d. What is the correlation coefficient determined by your calculator? e. Use your regression line to predict the value of the car in 2012 (remember, year 0
is 2003). Is this a reasonable prediction? Why or why not? Lab5 Page 2 of 5 5. Plot the points given on a scatter plot. x 1 1 2 2.5 3 3.5 4 4 4.5 5 5 5.5 2 y 1 2 1.5 2.5 3 3 3.5 4 4 5 6 6 6 5.a.Calculate the regression line for the data and sketch it on the plot. Lab5 Page 3 of 5 5.b. An outlier on a scatter plot is an observation that is far from the regression
line so it produces a large residual. Label the outlier for this graph “Point A.” 5.c.Calculate the regression line for the data without “Point A” and sketch it on the
plot in a different color. 5.d. Comment on the effect “Point A” has on the regression line for the data. 6. Consider this new set of data and accompanying scatter plot.
x
y 1
3 1.5
2 2
3 2
4 8
7
6
5 Lab5 Page 4 of 5 2.5
1 2.5
2 3
1 3
2 3
3 3.5
2 4
3
2
1
0 1 2 3 4 5 6 7 8 9 a. Draw a line where you predict the regression line for this set of points will lie.
b. Identify the potential outlier for this data as “Point B.” c. Calculate and graph the regression lines for the data points with and without
“Point B.” d. Comment on the difference in the two lines. e. Both “Point A” and “Point B” are considered outliers for their data sets. Which
would you classify as an “influential point?” Lab5 Page 5 of 5

AccountingQueen

(3)

Status NEW Posted 20 Aug 2017 07:08 AM My Price 10.00

Hel-----------lo -----------Sir-----------/Ma-----------dam----------- T-----------han-----------k y-----------ou -----------for----------- us-----------ing----------- ou-----------r w-----------ebs-----------ite----------- an-----------d a-----------cqu-----------isi-----------tio-----------n o-----------f m-----------y p-----------ost-----------ed -----------sol-----------uti-----------on.----------- Pl-----------eas-----------e p-----------ing----------- me----------- on----------- ch-----------at -----------I a-----------m o-----------nli-----------ne -----------or -----------inb-----------ox -----------me -----------a m-----------ess-----------age----------- I -----------wil-----------l

Not Rated(0)

• Buy Answer