The key identifying factor of a causal comparative study is that it compares two or more groups on a dependent variable. Therefore, a research question for a causal comparative study will read as follows: There is no significant difference between [define the two groups] on [dependent variable]. For example, "There is no significant difference between males and females on interest in reading." If there are three or more groups, then the research hypothesis should be slightly rephrased. An example is socioeconomic status whereby children are placed into three socioeconomic status groups: high, medium, and low. Instead of defining all three groups, state that there is no significant effect of the variable: There is no significant effect of [independent variable] on [dependent variable]. For example, "There is no significant effect of socioeconomic status on children's interest in reading."
Experimental or Quasi-Experimental
They key identifying factor of experimental and quasi-experimental designs is that they examine the effect of a treatment on a dependent variable. The literacy study that examines the effect of telling stories on literacy skills should be an experimental study. Research Hypotheses for this design should read as follows: There is no significant effect of [treatment] on [dependent variable].
There is no significant effect of telling stories on children's reading fluency.
There is no significant effect of telling stories on children's reading comprehension.
There is no significant effect of telling stories on children's vocabulary.
There is no significant effect of telling stories on children's interest in reading.
Correlational
Correlational designs examine the relationship between two variables within the same group of individuals. Research hypotheses for correlational