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About Me!

Dr. Tollefson has over 20 years experience in technical and scientific fields. Her Ph.D. and M.S. in statistics are from Iowa State University and her B.A. in physics is from Reed College. She, also, has taken several courses in economics, both from Harvard University's extension college and, at the graduate level, from Iowa State University. Dr. Tollefson's dissertation was on the problem of nonresponse in survey samples.

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BUSINESS ADVICE

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DATA ANALYSIS

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FINDING DATA

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WRITING REPORTS

FOR SCIENTIFIC RESEARCHERS

Data Analysis - Data Reduction - Sampling Plans - Plots

You might find the Sunspot Cycle of Interest as a Scientific Researcher:

(Click the graph to see bigger) Plotting the smoothed Average Number of Sunspots per Day for each month since 1749 is of interest if you are a Climate Scientist since Solar Flux appears to be related to the Sunspot Cycle.

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"I really enjoyed working with Margo. Her expertise in statistics helped me validate a complex sampling plan and the formula needed to estimate the sample size based on statistics collected during a pilot study. These equations were then validated by a third party organization and have been since then used widely in our sampling efforts to assess the actual impact of clean cookstoves projects in the developing world."

-Posted on: July 11 2016

"Here are new plots for sun spot number and temperature anomaly, going back to 1749 for the sun spots and to 1750 for temperature anomalies. The sun spot data is a revised series of monthly averages of daily sun spot numbers from SIDC in Belgium and the temperature data is from Berkeley and for land temperatures."

-Posted on: July 15 2015