Question

Students have shown that children in the US who have been spanked have a significantly lower IQ score on average than children who have not been spanked.

A) What is the explanatory variable in these studies? What type of variable is it?

B) What is the response variable in these studies? What type of variable is it?

C) Do you think these studies were observational studies or experiments? Explain.

Answer 1

Solution: A) In Statistics, explanatory variable is the one independent variable which is used to predit or explain differences in other variable. It is the variable, changing which we get the different values of the dependent variable, which is the variable of interest.

In this study, spanking of children in the US is the explanatory variable. Observing whose changes we can get the different valus of the IQ score of the children.

B) In Statistics, explanatory variable is the dependent variable. It is what we measure and which is affected in the experiment.  

In this study, the variable of interest is the IQ score of the children in the US. So, it is the explanatory variable.

C) By definition we know that experimental studies are those where investigators apply treatments to experimental units. There is involvement of treatment and control groups in experimental study.

And observational study is the one where investigators observe subjects and measure variables of interest without assigning treatments to the subjects.

In this question, the spanking of the children were done randomly, with no particular control or treatment being imposed on them. So, this is an observational study where researchers might have observed the IQ scores of US children and asked the spanking using a questionnaire.