Question

A cognitive psychologist would like to evaluate the claim that the omega-3 fatty acids can help improve memory in normal adult humans. One group of participants is given a large dose of fish extract containing the Omega-3 (500 mg), and a second group is given a placebo containing no Omega-3 (0 mg). The researcher asks each participant to read the front page of a local newspaper thoroughly every morning and to take their prescribed dosage (of either Omega-3 or placebo) immediately afterwards. The researcher gives each participant a memory test at the end of two weeks and records how many news items each participant remembers from the past three weeks of news. Answer the following:
A) What names would you give the independent and dependent variables;
B) Is the dependent variable discrete or continuous?
C) What scale of measurement (nominal, ordinal, interval or ratio; and continuous or discrete) is used to measure the independent variable?
D) What research method is being used (experimental or observational)? Explain why you conclude that the research method is one or the other.

Answer 1

Answer:

(a)

• Independent Variable- Dosage of Omega-3 Fatty Acids

• Dependent Variable - Number of news item remembered

(b)Discrete

(c)Ratio Scale and Discrete Variable

(d) Experimental Method

Step-by-step explanation:

The psychologist wants to evaluate the claim that omega-3 fatty acids can help improve memory in normal adult humans.

(a)In the study, the participants in the two groups were given fish extracts containing Omega-3 (500 mg) and no Omega-3 (0 mg).

The memory test involves measuring the number of items each participant remembers from the past three weeks of news.

Therefore:

• Independent Variable- Dosage of Omega-3

• Dependent Variable - Number of news item remembered

(b) The dependent variable is discrete since the number of news items remembered can only be whole numbers.

(c)The independent variable is in milligrams of Omega-3 where the placebo is 0 mg. This is a ratio scale since it has an absolute zero.

Since the dosage is given in multiples of 50mg, it is a discrete variable.

(d)Since the psychologist seeks to manipulate the conditions of the study by introducing Omega-3 to some of the participants and placebo to other participants, it is an experimental distribution.