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Final Fit

Now, plot the data to see how well your new model appears to fit the data. Remember to use the easyplot command:

easyplot 0.5 10.0

Screen capture of the POW plot window showing the results of the
	fitting the revised model with a notch for the absorption line.

Screen capture of the POW plot window showing the results of the fitting the revised model with a notch for the absorption line.

Answer these questions about your current model and plot:

  • Note the chi-squared for this fit.
  • How has the chi-squared changed since your first model? Does this change indicate that the fit is better or worse?
  • How has the chi-squared changed since you added the notch? Does this change indicate that the fit is better or worse?
  • Looking at your plot, how well does the model match the data? How has the fit of the model to the data changed since your first plot?
  • Zooming in on 6.0 to 8.0 on the x-axis (easyplot 6.0 8.0), does the model fit the absorption line better than before?
  • Do you think that you have found the best model for these data? Why or why not?
  • If not, then describe what features of the data the model seems to be missing.

If words seem to be missing from the articles, please read this.

Imagine the Universe! is a service of the High Energy Astrophysics Science Archive Research Center (HEASARC), Dr. Alan Smale (Director), within the Astrophysics Science Division (ASD) at NASA's Goddard Space Flight Center.

The Imagine Team
Project Leader: Dr. Barbara Mattson
Curator: J.D. Myers
Responsible NASA Official: Phil Newman
All material on this site has been created and updated between 1997-2014.
This page last updated: Thursday, 25-Mar-2010 08:54:52 EDT