Question

A Year 13 Statistics student was given an assignment where she had to design and conduct an experiment and analyse the data collected.

She decided to investigate whether being told that a quiz was easy or hard influenced the results of the quiz. All the students in a Year 9 class were given the same quiz after having been randomly allocated to one of three groups: Group 1 were told that it was a hard quiz, Group 2 were told it was an easy quiz and Group 3 were told nothing about the quiz. None of the students were told what the experiment was about.

She then carried out a randomisation test to compare the mean quiz marks for the three groups.

Which one of the following statements is false?

The response is the quiz mark.

There were 3 treatments; being told the quiz was easy, told it was hard or told nothing at all.

It was not possible to blind the students because they knew that they had been given a quiz.

The experiment used a completely randomised design.

The group that were told nothing about the quiz could act as the Control group.

Answer 1

Solution

It was not possible to blind the students because they knew that they had been given a quiz. Answer

Explanations

’All the students in a Year 9 class were given the same quiz after having been randomly allocated to one of three groups and carried out a randomisation test to compare the mean quiz marks for the three groups’ => the response is the quiz mark and so it is not false.

’All the students in a Year 9 class were given the same quiz after having been randomly allocated to one of three groups and Group 1 were told that it was a hard quiz, Group 2 were told it was an easy quiz and Group 3 were told nothing about the quiz.’ => there were 3 treatments; being told the quiz was easy, told it was hard or told nothing at all. Hence, it is not false.

’All the students in a Year 9 class were given the same quiz after having been randomly allocated to one of three groups and carried out a randomisation test’ => the experiment used a completely randomised design. Therefore it is not false.

‘Group 1 were told that it was a hard quiz, Group 2 were told it was an easy quiz and Group 3 were told nothing about the quiz.’ => the first two were treatment groups and the last is a Control group. So, the last statement cannot be false.

By elimination, second statement is false. Also, ‘Group 1 were told that it was a hard quiz, Group 2 were told it was an easy quiz and Group 3 were told nothing about the quiz.’ => the participants were told about the quiz.

DONE