Biological Statistics
Homework 4
Due Tuesday, Oct. 3

You must type your answers for this assignment.

  1. Ketterson and Nolan (1976) investigated the sex ratio of the dark-eyed junco (Junco hyemalis) during the winter. In the four largest geographic samples (from a much larger data set), they found the following results: 
    Location     females     males
   E            67         33
   I            58         60
   J            70         75
   P            55        106
    Analyze the data using a repeated G-test of goodness-of-fit.
    2. Bar graph
  2. Flip through your favorite scientific journal until you find a graph with vertical bars around the means (commonly called "error bars"), like the one above. Tell me what the bars represent: standard deviation, one standard error, two standard errors, 95% confidence limits, etc. If the paper doesn't say what the bars are, tell me that. Also list all of the variables shown on the graph, and say whether each one is an attribute or measurement variable. Give the citation information (authors, year, article title, journal, volume, page numbers). Print or photocopy the page with the graph on it (not the whole article) and attach that to your homework.

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This page was last revised September 28, 2006. Its URL is http://udel.edu/~mcdonald/stathw4.html