Sia vs silence

The following activity is an assessment I do at the end of my research methods unit. It is a first attempt at something that begins to feel like an internal assessment. Students carry out an experiment together and then write up the responses for homework. Both the activity and sample answers are included below.

The task

In class, we carry out the following experiment.

To begin with, I randomly draw names out of the hat so that half of the class is sent out into the hallway while the other half stays to carry out the first condition of the experiment.

To begin, I give each student a blank sheet of paper.  I tell them that they are going to hear and see a list of 25 words.  The goal is for them to recall as many words as possible.  The order in which they are recalled is not important.

The Google presentation of the list is here.

For each word, I show it for three seconds.  At the end of the list, I close the presentation and give them one minute to write down as many of the words as they can remember.

I then collect all of the papers from Group 1.

Group 2 then comes into the room.  The same directions are given to the group, except that this time, I play Sia's I want to fly from the chandelier. Please note that I do not show the video, I only play the music. At the end of the list, I close both the presentation and turn off the music.

Once again, they have one minute to write down the words they remember. At the end of the minute, I collect all of the lists.

In order to speed up the data collection, I then pass out the group 1 lists to people in group 2 and vice versa. I then run through the list and ask them to count how many words were correctly recalled. I enter all the data into a Google spreadsheet which I then share with the class.

To finish, I ask them to take the following notes about the experiment:

  • All words were five-letters long.
  • Words were chosen through the use of a random word generator.  I chose 40 words and then eliminated words that I thought might not be recognized by students.
  • All words were shown for three seconds
  • They had one minute to write down as many words as possible.

At this point, student are ready to begin their assessment.  I have them work in class on their own for the rest of the period.  Then they complete the assessment for homework.

Student copy of assessment

Potential answers

1. What was the null hypothesis of our study? (3 marks)

There will be no significant difference in the number of five-letter words recalled from a 25-word list by high school students when both shown and read a list in silence or with music.

2. What was the independent variable? (2 marks)

The presence of music - that is, whether or not music was played while the participants were shown and read the list of words.

3. What was the dependent variable? (2 marks)

The number of five-letter words recalled from a 25-word list.

4. Write a short summary of the procedure of our experiment. (4 marks)

See the procedure above.

5. What was the mean and median score for our experiment? What does this data tell us? (4 marks)

This will depend on the data that is collected.  The mean should tell them the average score.  Ideally, they would also calculate the standard deviation to see how much the mean really tells them. The median will tell them a score for which 50% of the sample scored that score or below, and 50% scored that score or higher. They should be able to explain this in terms of the experiment that they do in class.

6. Graph the results of the experiment. (5 marks)

The graph will depend on the data. See the points below in the assessment guide.

7. Calculate the Mann Whitney U for this experiment.  What does the test tell us – that is, what conclusion can we draw? (3 marks)

Once again, this all depends on the data.  Have students use a two-tailed test as we are not sure if the music will increase or decrease the ability to recall the list of words. If the p value is less than 0.05, they can reject the null hypothesis.  It would appear that the presence of Sia's music has a positive (or negative) effect on one's ability to recall a list of words.  If the p value is greater than 0.05, then they will retain the null hypothesis and argue that it appears that listening to Sia had no significant effect on the ability to recall a list of five-letter words.

8. Write an evaluation of our study.  What were three limitations of our study? (6 marks)

See examples of limitations below.

9. If you were going to do this experiment again, what is one recommendation you would make in order to improve the study? (3 marks)

For example, a repeated measures design could be used to eliminate participant variability.  However, the same list could not be used in both conditions, so the conditions would have to be counter-balanced.

Or, use a list of four digit numbers instead of words in order to get rid of the effect of the meaning of the words.

Use a piece of music that would be unfamiliar to the students to eliminate the variable that some of the students would sing along in their head.

Assessment guide

1.  Null hypothesis - award one mark for each of the following

  • The concept of a null hypothesis (no significance difference...)
  • An operationalized IV and DV
  • The target population.

2. Independent variable

  • One mark if the student writes "music."
  • If the IV is operationalized, then two marks.

3. Dependent variable

  • One mark if the student writes "number of words."
  • If the DV is operationalized, then two marks.

4. Procedure - award one mark for each of the following

  • Explanation of the design
  • Explanation of random allocation of participants
  • Explanation of how the materials were created.
  • Explanation of what happened in each condition

5. Descriptive statistics - award one mark for each of the following

  • Correct calculation of the mean
  • Correct interpretation of the mean
  • Correct calculation of the median
  • Correct interpretation of the median.

6. Graphing the data - award one mark for each of the following

  • Creating a bar graph - with the bars not touching (that would be a histogram)
  • Correctly labeling the x axis: treatment conditions - with and without music
  • Correctly labeling the y axis: number of words recalled
  • No distortion of the graph: the y axis should start at 0 and go up to 25.
  • A correct title of the graph that reflects the hypothesis of the experiment.

7. Inferential statistics - award one mark for each of the following

  • Correct calculation of the Mann Whitney test
  • Correct statement of the p value and its implication for the null hypothesis (reject or retain)
  • Correct conclusion with regard to the effect of the IV on the DV

8. Evaluation - award two marks for each correct limitation. 

Limitations include but are not limited to:

  • The use of an independent samples design means that there is participant variability with regard to the ability to memorize.
  • Familiarity with the music may be a confounding variable.  Those that were "singing along in their heads" may have had more problems with recall than those that did not.
  • The sample is a sample of opportunity.  It is not representative of the entire population and may not be generalizable.
  • The recency effect may have taken place where people remembered the words that were most recently said - as they were still in STM.
  • Some of the words on the list may have had more personal meaning to participants to others and may have been more easily recalled.

Remember, any mistakes made by you in carrying out the experiment are not limitations.  They are mistakes - and if this were a real experiment, you would have to redo the study. Remind them that the IB does not accept mistakes as limitations.

9. Modification - award one mark for each of the following

  • An appropriate modification
  • Identification of a limitation that the modification addresses
  • Explanation of why the modification would make a difference.
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