Question

You design an experiment to determine whether a chemical will affect the amount of peptidoglycan in a species of gram-positive bacteria. You classify each individual as either normal peptidoglycan (cell stains in a normal way), reduced peptidoglycan (cell stains but the stain is patchy), or absent (no stain). Under normal conditions, 10% of cells do not stain, 7% show patchy staining, and 83% stain normally. Test whether the chemical alters the amount of peptidoglycan from the expected proportions.

Normal = 145, reduced = 180, absent = 165

1. Which test would you use?
2. Statistical null hypothesis?
3. Statistical alternative hypothesis?
4. Test statistic
5. Degrees of freedom
6. Critical value
7. P value
8. Whether you fail to reject or reject the statistical null hypothesis

Answer 1