Biometry
Stat 412


Lab Assignment #3

Important: Read all of this handout before starting!!!

Goals:

1) Testing statistical hypotheses
2) Computing chi-square values
3) Analyzing contingency tables

Assignment: implement the following procedures using MINITAB.

1. The "handedness" of men was studied in a random sample of 81 men by noting if they were right- or left-handed. Results: right-handed =56; left-handed =25. Test the hypothesis that handedness occurred at equal frequency using chi-square.

2. The color of slate pencil urchins was studied on the reef at Puako, Hawaii. Urchins occur in three colors: red, white, and pink. Data were collected by randomly sampling 124 individuals and noting their color. Results: red=24; white=30; pink=70. Test the hypothesis that the colors occurred at equal frequency using chi-square. Test the hypothesis that the colors occurred at 1:2:1 (red: pink: white) frequencies using chi-square.

3. Observations were made on ornate butterflyfish (Chaetodon ornatissumus) at Richardson’s Ocean Park, Hawaii, during both the day and night on the number of bites taken on different species of corals.

Number of bites observed

Coral

Day

Night

Montipora flabellata

6

85

Montipora patula

47

30

Montipor verrucosa

81

5

Test the hypothesis that the number of bites taken on different species of corals did not vary with time of day using a contingency table.

  1. A study was conducted on the number of positive allergic responses of men and women to three different drugs.

Number of allergic responses observed

 

Men

Women

Drug A

15

85

Drug B

30

30

Drug C

180

5

    Test the hypothesis that the number of allergic responses did not vary among men and women.


This assignment is due next MONDAY, 9/24,  in class