Question

in my experiment, i noticed that the opening and closing of a goldfishs gill cover is correlated to the breathing of the fish. after seeing what other people have done, i have come to think that the respiratory rate of goldfish can be affected by nicotine. in my experimental design, i have 40 fish equally divided into two 10 - gallon tanks. each group of fish is fed 0.1 mg of fish food twice a day. the temperature and lighting for both tanks are identical. the first group of fish, group a, are fed nicotine in addition to their regular food. the second group of fish, group b, do not receive any additional food. i measured the respiratory rate of the fish in both groups and i determined that the average respiratory rate for the group a fish is greater than the respiratory rate for the group b fish by 12.3 breaths per minute.

1. what is the independent variable in this experiment?
2. what is the first step of the scientific method called?
3. what is the fourth and final section of a formal scientific journal article called?
4. what type of data is not mentioned in the narrative above?
5. how would the null hypothesis be phrased for this experimental design?

Explanation:

1.

The independent variable is the factor manipulated in an experiment. Here, Group A gets nicotine (added to food) and Group B doesn't, so nicotine (or the addition of nicotine) is the independent variable.

The first step of the scientific method is making an observation (or asking a question based on observations). In the text, the author noticed gill cover movement and thought about nicotine's effect, starting with observation.

A formal scientific journal article typically has sections: Introduction, Methods, Results, Discussion. The fourth and final (main) section is Discussion, where results are interpreted.

Answer:

The independent variable is the addition of nicotine (or "nicotine" as the factor being manipulated).

2.