Biology 401 - Biometry

Fall 2002

Sample Questions for Exam 4

Note - there are more questions in this sample than there will be in the real exam

Test significance at alpha = 0.05 unless otherwise indicated.

  1. A psychologist is testing a group of 40 TV addicts with a word association game, in which the subject responds to a word with the first word that pops into his head. The psychologist wants to determine if these people are abnormal in their responses by comparing the frequency of each response to those in the "normal" population. Are these people a bit off-the-mark? (Data also in Excel worksheet.)
    Test word: "Blanket"

    Response Frequency in
    general population (%)
    Number of test
    subjects giving response
    Bed 55 10
    Warm 25 6
    Comfort 10 2
    Leroy 0 13
    Tuberculosis 0 7
    Other response 10 2








  2. You want to test the hypothesis that the likelihood of retinal detachment is related to eye color. You examine 100 people with detached retinas and 100 control subjects and obtain the counts shown below. Create a null hypothesis and test it using an appropriate method.
    Detached retina: Blue eyes = 32 Brown eyes = 51 Other = 17
    Normal: Blue eyes = 37 Brown eyes = 40 Other = 23










  3. One hundred random people were surveyed and asked whether a) they smoked and b) they coughed heavily in the morning. Is there a difference in the proportion of coughers between smokers and non-smokers? Use any method desired to address this question. (Data also in Excel worksheet.)
      Smoke?
    Cough? Yes No
    Yes 18 7
    No 12 63



  4. A study has just been completed examining the issue of mate choice as it affects that bizarre creature, the science geek. In an experiment representing a cross between Survivor and Club Med, 50 geeks and 100 normal people were left on a tropical island, and a year later researchers assayed who was romantically involved with whom. They found that, of the 75 couples, 40 were normal/normal, 20 were geek/geek, and 15 were normal/geek. Do geeks and normals appear to choose their mates at random, or is there a bias in their selection?












  5. During an epidemic in a city, you are trying to determine whether new cases of the disease are appearing at random, or instead tend to cluster together. You have a map of the city showing how many cases have appeared in each square block. What hypothesis might you want to test, and how would you go about testing it?





  6. You are studying the pattern of depolarization in a neuron from the brain of a banana slug. Over a two-hour period, you measure the number of depolarizations per minute (data in Excel worksheet). Can you reject the hypothesis that the timing of the depolarizations is random?






  7. A new stop-smoking product, the Oral Patch, is being tested for effectiveness in keeping people from starting to smoke again while using the product. The patch, which is placed over the user's mouth, is being compared to a more traditional nicotine-laced skin patch. A "survival" table is created for the 100 people tested for each product, showing how many individuals started smoking or were lost each week. Using this data (in the Excel worksheet), finishing constructing the suvival tables and then compare the effectiveness of the two products.