Question

Neckties and bacteria: A group of researchers investigated the contamination of medical personnel clothing at a New York hospital since there is a potential for patient exposure to potentially dangerous bacteria. They sampled neckties worn by physicians, physician assistants, and medical students at a teaching hospital in New York. Nearly half (47.6%) of the neckties tested harbored microorganisms that can cause illness. By comparison, only one of the 10 ties worn by security guards tested positive for a disease-carrying microorganism. The researchers want to determine if the difference is statistically significant.

Which of the following is an appropriate statement of the null hypothesis?

A. The proportion of contaminated ties from medical personnel is the same as the proportion of contaminated ties from security guards.B. The proportion of contaminated ties from medical personnel is not the same as the proportion of contaminated ties from security guards.C. The proportion of contaminated ties from medical personnel is greater than the proportion of contaminated ties from security guards.

Answer 1

Explanation:

The null hypothesis never contains terms such as less than or greater than. Also, the null hypothesis does not contain the term, ≠

The alternative hypothesis us always the opposite of what the null hypothesis claims.

Since we are comparing two proportions and the researchers want to determine if the difference is statistically significant, this statement is the alternative hypothesis and contains ≠. Therefore, the null hypothesis, containing = would be

A. The proportion of contaminated ties from medical personnel is the same as the proportion of contaminated ties from security guards.