Question

having at least one 30 - minute warm - up session per week resulted in a drastic reduction in tears in the meniscus. in a study involving about 5500 adolescent boy hockey players in a certain one group was randomly assigned to warm up with a neuromuscular exercise session. this group had 57% fewer meniscus tears than the control group. complete parts a through d below

a. being boy and not being boy
b. tearing one’s meniscus and not tearing one’s meniscus
c. having at least one 30 - minute neuromuscular warm - up exercise session per week and not having a warm - up session
d. playing hockey and not playing hockey
what is the response variable?
number of meniscus tears in each group
gender
whether or not the exercise was done
sport played
c) give one statistical advantage of using only boys from the specified country who played hockey in this study. choose the correct answer below
a. the population is sufficiently large that a sample of 5000 adolescent boy hockey players does not appear to have been difficult to take.
b. participants with very similar backgrounds are more likely to follow the exercise routine together.
c. fixing the gender, sport, and nationality of the participants has produced very favorable results.
d. less variation in meniscus tears would be expected among players of the same gender in the same sport.
d) give one statistical disadvantage of using only boys from the specified country who played hockey in this study. choose the correct answer below
a. the conclusions of the study cannot be generalized to girls, boys in other countries, or to players of other sports.
b. people who do not play sports are far less likely to tear their meniscus.
c. meniscus tears are not common in hockey. athletes from a different sport would have been a better test for this exercise.
d. fixing the gender, sport, and nationality of the participants means that the sample is not composed of the best athletes in the world.

Explanation:

Part (a) (assuming the first question was about treatment groups, but since the selected option is C, we'll confirm)

The study's treatment is the neuromuscular warm - up session. So the two groups are those who have at least one 30 - minute neuromuscular warm - up per week and those who don't. Option C matches this as the treatment variable is the warm - up session, so the two groups are defined by having or not having the warm - up. Options A (gender) and D (sport participation) are not the treatment here, and B (meniscus tear status) is the response, not the treatment group definition.

A response variable is what is being measured or observed in a study. In this study, we are looking at the effect of the warm - up on meniscus tears. So the number of meniscus tears in each group is what we are measuring (the response). Gender (A) and whether the exercise was done (C) are explanatory variables, and sport played (D) is a characteristic of the sample, not the response.

When we use a homogeneous group (same gender, sport, nationality), there is less variation in the response variable (meniscus tears) because other factors that could affect meniscus tears (like gender - related differences in anatomy, sport - specific injury risks) are controlled. Option A is about sample size ease, not a statistical advantage of homogeneity. Option B is about following the routine, not a statistical advantage. Option C is incorrect as "favorable results" is not a statistical advantage of homogeneity. Option D correctly states that less variation in meniscus tears is expected in a more homogeneous group.

Answer:

C. Having at least one 30 - minute neuromuscular warm - up exercise session per week and not having a warm - up session

Part (b)