Question

does a platelet - rich plasma (prp) injection into the scalp promote hair growth? researchers identified 50 female patients with female pattern hair loss. the patients ranged in age from 30 to 60 years. for each patient, two areas with hair loss were identified. a coin toss was used to decide which area received the prp injection and which received a saline injection. injections were given to each patient at one - week intervals. after 6 months the change in the patients hair density (number of hairs per square centimeter) and hair diameter (millimeters) was measured. the mean difference in hair density (pcp minus saline) was 64.41 \\( \frac{hairs}{cm^{2}} \\) and the mean difference in hair thickness was 0.07 mm. complete parts (a) through (g) below. b. female pattern hair loss c. hair diameter d. gender e. age (d) what is the treatment? a. the treatment is hair growth and it is set at two levels: platelet - rich plasma (prp) injection or saline injection b. the treatment is hair growth and it is set at two levels: hair density or hair diameter. c. the treatment is the injection and it is set at two levels: hair density or hair diameter. d. the treatment is the injection and it is set at two levels: platelet - rich plasma (prp) injection or saline injection.

Explanation:

In an experiment, the treatment is what is being applied to the subjects. Here, the researchers are applying either a platelet - rich plasma (PRP) injection or a saline injection. Hair growth is the response variable (measured by hair density and hair diameter), not the treatment. Options A and B incorrectly state that the treatment is hair growth. Option C is wrong as hair density and hair diameter are response variables (outcomes of the treatment), not the treatment itself.

Answer:

D. The treatment is the injection and it is set at two levels: platelet - rich plasma (PRP) injection or saline injection.