A Biologist Is Interested in the Relationship Between Susceptibility to Certain

A biologist is interested in the relationship between susceptibility to certain carcinogens and gender. To test this hypothesis, a simple random sample of 1200 male rats is selected while, independently, a simple random sample of 1200 female rats is selected. The three carcinogens are the microbial carcinogen aflatoxin B₁ and two viral carcinogens, hepatitis B and human papillomavirus (HPV) , which have both been found to cause cancer in humans. The rats were randomly assigned to receive one of the three carcinogens, with each carcinogen being given to 400 rats of each gender. The following table summarizes the number of rats of each gender that developed a tumor under a given treatment:
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$$\begin{array} { | l | c | c | } \hline & { \text { Gender } } \\\hline { \text { Carcinogen } } & \text { Male } & \text { Female } \\\hline \text { Aflatoxin } B _ { 1 } & 96 & 295 \\\hline \text { Hepatitis B } & 32 & 45 \\\hline \text { HPV } & 94 & 40 \\\hline\end{array}$$ Which hypotheses are being tested by the chi-square test?

A) The null hypothesis is that carcinogen susceptibility and gender are independent in rats, and the alternative hypothesis is that they are dependent.
B) The null hypothesis is that the mean level of carcinogen susceptibility is the same for both genders of rat, and the alternative hypothesis is that the means differ.
C) The distribution of carcinogen susceptibility is different for male and female rats.
D) The distribution of gender is different for the three different carcinogens.