A group of educators want to determine how effective tutoring is in raising stud

Question

A group of educators want to determine how effective tutoring is in raising students' grades in a math class, so they identify a group of 30 students and randomly assign half of them to receive free tutoring and the other half do not. Then they compare final exam grades for the group that took advantage of the tutoring and the group that did not. Suppose the group participating in the tutoring tended to receive higher grades on the exam.

This study does not mention whether it was conducted to be a double-blind study.

Suppose that the students know which group they are in for this study. What bias might occur?

Suppose that the educators know which group each student is in for this study. What bias might occur?

A group of educators want to determine how effective tutoring is in raising students' grades in a math class, so they arrange free tutoring for those who want it. Then they compare final exam grades for the group that took advantage of the tutoring and the group that did not. Suppose the group participating in the tutoring tended to receive higher grades on the exam.

Is this an observational study or a controlled experiment? Why?

Does this study show that the tutoring worked? If not, explain why not and suggest a confounding variable.

Explanation / Answer

Double blind study is one in which neither the researcher nor the subject knows who is in the study. However,This study does not mention whether it was conducted to be a double-blind study. A Random sample of 30 students are considered for this experiment. There is definately a chance of bias, reason being , this is not a homogenous population. Possibilities of having extremely bright students and there may also be student who have less grasping power to maths subject.

Let's consider the 2 cases as stated. Suppose that the students know which group they are in for this study. I this case there is a possibility that the student who took tutoring may put in less effort assuming that he is getting double trained on the subject And also the student who does not take tutoring may put in more efforts that usual or may get demotivated and put in less efforts. so there will be bias.

Suppose that the educators know which group each student is in for this study. In this case the educator may tend to be more inclined towards the students who took tutoring and be more strict in evaluating the exam results as he knows that they are dounble trained and be lineant in evaluating exams for those students who did not take tutoring. There is a Bias in this case as well.

For the second scenario : It is an Observational study because, In an observational study investigators observe subjects and measure variables of interest without assigning treatments to the subjects. The treatment that each subject receives is determined beyond the control of the investigator. One of the hallmarks that separates types of experiments is to ask yourself "Who decided which treatment a subject would receive?" If the subjects themselves chose, then its usually what we call an observational study. Here tutoring was provided for those who want it.

Whereas if it was the 1st scenario where they identify a group of 30 students and randomly assign half of them to receive free tutoring and the other half do not, then it is an Experimental study.

Q) Does this study show that the tutoring worked? If not, explain why not and suggest a confounding variable.

A confounding variable is an outside influence that changes the effect of a dependent and independentvariable. This extraneous influence is used to influence the outcome of an experimental design. Confounding variables can ruin an experiment and produce useless results.

self Efforts and self motivation from the student and the bias of the Teacher are the confounding variables may affect the outcome of the study .

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