A cognitive psychologist would like to evaluate the claim that the omega-3 fatty acids in fish can help improve memory in normal adult humans. One group of participants is given a pills containing a large dose of fish extract containing the Omega-3 (500 mg per day), and a second group is given a placebo (sugar pill). The researcher asks each participant to read the front page of the local newspaper thoroughly every day and to take one pill every day. 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 questions about this scenario: 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.

Independent variable also known as controlled variable are those variables that their values do not depend on or affected by the state of any other variable in the experiment.

It is the condition that can be altered in an experiment. It is the variable you control

While the dependent variable are the response or results of an experiment because we are assessing how it responds to a change in the independent variable, so you can think of it as depending on the independent variable.

The independent variable is the Memory test, which proves how much information participants were able to retain from the articles.

b.

The dependent variable, Memory Test is continuous variable.

A variable is said to be a continuous variable if it can take on an uncountable set of values.

Memory test can't be measured in numbers; it can only be evaluated based on reasoning.

c.

The Ratio scale of measurement are used sto represents quantity and has equality of units:

Here, the independent variable are measured in milligrams (500mg, daily).

2 of it is 1000mg; none of it is 0mg which means there's no quantity of the fish extract.

And it is a Discrete Variable because it can take a particular range of Value (i.e. 500mg, daily)

d.

The above research is an experimental research method because it involves the psychologist assigning subjects (the fish extract and platob) to treatments for the purpose of seeing what effect (the memory test) the treatments have on some response.