School

Rutgers University, Newark **We aren't endorsed by this school

Course

ECONOMICS 223

Subject

Statistics

Date

Sep 25, 2023

Type

Other

Pages

4

Uploaded by GeneralOxide15300 on coursehero.com

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f(x) = − 0.08 x + 168.44
R² = 0.79
September Sea Ice Extent (1,000,000 sq km)
Year
September Sea Ice Extent (1,000,000 sq km)
2. Plot a scatter plot of the data. In your own words, describe the data.
The data seems to be on a down trend.
3. Fit a linear trend to the dataset. Based on the linear trend, what is the rate of change of the
Arctic sea ice? What is the intercept? What is the R2 value for this trend?
The rate of change is -8.12*10^-2 (1,000,000 sq km) per year.The intercept is 168.44. The R-
squared value is .7935
4. Based on the rate calculated in question 3. When do you think that Arctic Sea Ice area will
reach zero? Discuss any issues that may occur with these types of models (is it realistic? Why
or why not?)
Based on the model, the artic sea ice area will reach zero in 2074. I believe the model is realistic
if no action is taken to control the loss. This is a good model to show us what will happen if
action isn't taken soon.
5. Using the "Regression" function (instructions provided in assignment 4) calculate an error
on the slope and the intercept
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The standard error on the intercept is 12.9 and the standard error on the slope is 6.47*10^-3
6. Calculate the predicted data and the residuals from your fit. Plot the residuals on a scatter
plot. What do you observe about the residuals? Comment on the goodness of fit. Provide the
graph in your write up.
The residual seem to be scattered which indicated that the equation is a good fit for this data.

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Residuals
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Residual
7. Plot a histogram of the residuals. What do you observe about the histogram of the
residuals? Comment on the goodness of fit. Provide the graph in your write up.
That most of the residuals are in the middle of the histogram which indicated that they are very
close and there are very few "outliers"
8. To examine why, fit a linear trend to the data from 1979 to 2001 and compare it to a linear
trend to the data from 2002 to 2021. What are the rates of change for these time periods?
What are the intercepts? What are the R2 values? Compare the rates to the rate determined
in question 3 and comment. Based on these two new fits, why is the consensus view of the
melt rate of Arctic sea ice changing? Provide the graph in your write up.

For the first time period, the rate of change is -3.99*10^-2, the intercept is 86.384, the R-
squared is .2924. For the Second time period, the rate of change is -7.26*10^-2, the intercept is
151.08, and the R-squared is .4014. The rate of change of the first time period is a lot farther
than the second time period. The consensus view is changing probably because we have been
accelerating the melting in the past 20 year at almost double the rate than we have in the past.
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f(x) = − 0.07 x + 151.08
R² = 0.4
f(x) = − 0.04 x + 86.38
R² = 0.29
First half vs second half
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Resiudal
9. Plot the residuals for your two new trends. What do you observe about the residuals?
Provide the graph in your write up.
The residuals look evenly distributed above and below zero which makes them a good fit.
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First half vs second half resiudals
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Residual