Question

Answer questions 5-9 below using the information in this experimental description. Dr. Meyer wants to study the effect of Kava root on insomnia. She recruits 150 people who experience long term insomnia (more than 4 months experiencing insomnia) and divides them into two groups. One group of 75 individuals takes 125 mg of kavalactones one hour before bedtime. The other group of 75 individuals takes a placebo every day. For the duration of the study, the two groups follow two common guidelines: no added sugars or caffeine intake after 12pm and no screen time an hour before bedtime. Dr. Meyer follows the individuals during four weeks. She collects data on sleep patterns which include the number of hours slept each night and a scale of difficulty to fall asleep scored 1 to 5 (1 = feel asleep right away; 5 = more than one hour awake in bed).

5. 1pt. What is the independent variable?

6. 1pt. What is the dependent variable?

7. 1pt. What is the experimental group?

8. 1pt. Which is/are Dr. Meyer’s controlled variable(s)?

9. 1pt. Write a possible hypothesis for this experiment.

10. 1.5pts. Is the following statement a prediction or a theory? How do you know?

“If Vitamin C supplementation shortens the length of the common cold, then adults taking 1g of Vitamin C a day will recover from the common cold faster than adults who aren’t taking Vitamin C supplementation.”

Answer 1

1) An independent variable is a variable which can be manipulated or changed or controlled in a scientific experiment in order to test the effects on the dependent variable. Therefore, here in this given experiment the independent variable is the sleep (insomnia) because it is being manipulated by the researcher by giving kava root to the group of individuals.

2) A dependent variable is the variable which is being tested and measured in an experiment and it is being affected during the experiment. Here, in this experiment, kava root is being tested whether it is helpful in insomnia or not. Therefore it is a dependent variable in this experiment.

3) Experimental group is the group in an experiment in which the variable is being tested or the group who are receiving the variable and here in this case it is the dependent variable which is a kava root. So the experimental group is the group of 75 individuals who are receiving 125mg of kavalactones.

4) A control variable is a variable that is not changed throughout the experiment or is being kept constant by the researchers. In this experiment, the controlled variables are sugar, caffeine as their intake is prohibited after 12pm and screen time as it is prohibited an hour before sleep.

5) A possible hypothesis can be " If an insomniac patient is given 125mg kavalactones (kava root), then it is helpful in inducing sleep right away in 85% of patients if they are not being provided with sugar and caffiene after 12 pm and screentime before 1hour of sleep".

6) A prediction is an action of predicting future or a forecast of some event but a theory is a principle that is based on substantiated data, repeated testing and the consensus of group of researchers and it is a well established, tested explaination of the research.

The given statement is a theory as the effect of Vitamin-C in common cold is clearly being studied in two groups, one who take vitamin supplements and one who don't. The group who took vitamin supplements are benefited and who didn't take the supplements are not benefited. Here common cold is an independent variable whereas Vitamin-C is a dependent variable.