Kate Sanders, a researcher in the department of biology at IPFW University, studied the effect of agriculture contaminants on the stream fish population in northeastern Indiana. Specially designed traps collected samples of fish at each of four stream locations. A research question was, Did the differences in agricultural contaminants found at the four locations alter the proportion of the fish population by gender. Observed frequencies were as follows: Stream Location
Gender A B C D
Male 49 44 49 39
Female 41 46 36 44

a. Focusing on the proportion of male fish at each location, test the hypothesis that the population proportions are equal for all four locations. Use a 0.05 level of significance.
b. Does it appear that the differences in agricultural contaminants found at the four locations altered the fish population by gender?