Beryllium disease: Beryllium is an extremely lightweight metal that is used in many industries, such as aerospace and electronics. Long-term exposure to beryllium can cause people to become sensitized. Once an individual is sensitized, continued exposure can result in chronic beryllium disease, which involves scarring of the lungs. In a study of the effects of exposure to beryllium, workers were categorized by their duration of exposure (in years) and by their disease status (diseased, sensitized, or normal). The results were as follows:

Duration of exposure

less than 1 1 to less than 5 greater than or =5

Diseased 11 9 22

Sensitized 11 23 9

Normal 69 137 195

Test the hypothesis of independence. Use the a=0.05 level of significance and the -value method with the TI- Plus calculator. What do you conclude?

(a) State the null and alternate hypotheses.

: Beryllium exposure and disease status independent. (are or are not)

: Beryllium exposure and disease status independent.

(are or are not)