This post provides the notes for a workshop I ran at the Otago Mathematics Association (OMA) conference about using technology to design and carry out experiments online.
Actually, at the moment this post only provides a PDF of the slides I used for the workshop – I will update this post with more detail later this year 🙂 Links and documents referred to in the slides are at the bottom of this page.
A working demo of the random redirect tool in action for memory experiment – when you click this link, you will be sent to one of two versions of a Google form at random mathstatic.co.nz/auto/XHCNPYLP
I started work on a simple tool last year that would help students (and teachers) to conduct experiments online using Google forms. The plan was that the tool would take care of the necessary random allocation of treatments part of the experimental design through some background code that would send the respondent to one of two versions of the form (AKA random redirect tool).
But before we go any further….
Here is a link to a very short questionnaire to demonstrate the tool in action. You’ll be sent to one of the two versions of a survey. Complete the survey then come back here to read more 🙂
Later down in the post you will be able to see the results as they come in……….
So how did I set up the experiment?
Some people already know that I have a music degree as well as my science degree. So for this experiment, I decided to play around with how much impact music can have on how you interpret a movie scene. There are quite a few cool examples of the same scene set with different music out there in internet land (just ask Mr Google), and I went with the resources on this site http://midnightmusic.com.au/2011/06/an-intro-to-film-scoring-same-scene-5-ways/
I quickly created a questionnaire about pedestrian safety with a few “filler” questions to try to disguise the treatment used in the experiment (although I didn’t really try that hard). Once I was happy with the questionnaire, I created a copy of it and changed ONE thing only – which was the music accompanying the scene shown in “driveways safety” video. I then used the random redirect tool I’ve made available here http://www.mathstatic.co.nz/auto to create the link I shared earlier in the post.
When someone accesses the link created by the tool, code behind the scenes will select one of the two versions of the questionnaires at random and redirect the user to that version of the questionnaire.
The results so far….. brought to you by the not so awesome graphs available from Google sheets 🙂
Well at least it is not a pie chart (although they are the default chart for presenting categorical data from Google forms). This chart is “live” so depending on when you read this part of the post there may be little, or a little more than a little, data.
Google forms are really cool things to use for experiments, particularly if you exploit the ability to use page headers, sections, embedding videos and images as part of the form. I’m sure with using add-ons there are other awesome ways to attempt to manipulate people too. The Tricky questions exemplar task from NZQA for AS91583 Conduct an experiment to investigate a situation using experimental design principles is a task that would work really well using Google forms and http://www.mathstatic.co.nz/auto.
The basic idea behind developing these games is that you need to award points somehow, you need different levels of difficulty for the game and you need a way for the game to end ……. oh and you need to make it addictive! For this particular game, there is no points system and no way to move players up through levels. This (hopefully) gives a rich context to explore lots of statistics ideas 🙂
When thinking about how to use the game and the experiment lab in teaching statistics, a really important teacher understanding is that the data created from playing the game exists initially within an “experimenting world”, not a “sampling world”. So, unless you are going to use actual random samples from defined populations (e.g. a random sample of students from your school), then this game/data should not be used directly for teaching sample-to-population inference or for exploring sampling variation.
But you can definitely explore other sources of variation with this game, as well as important ideas around study design e.g. defining and measuring variables, carrying out an experiment etc. To get the “ball rolling” I’ll start with a few ideas, which are in no particular order and written as independent lessons/activities …………
How do you measure performance in the game?
The original version of the game only records the time to complete the game, so you could base your teaching around getting students to define or create other measures of performance. In the experiment lab, they can choose to measure other aspects of performance. Other measures could also be developed and measured by students e.g. how “stressed” a player felt during the game, whether they “rage quit” or not. If you do come up with other measures that you would like to add to the game, let me know and I’ll try to include them.
Here’s how I came up with the performance measures in the experiment lab…….
Originally I started with the time in seconds to “connect the dots” as the performance measure. I realised quickly that a second is actually quite a long time and that this was not accurate enough. Playing the game initially with the time measured to the nearest second could be used to do some teaching around measurement error e.g. if two players both get 4 seconds as the time recorded for completing the game, does this mean they both finished at exactly the same time? In the experiment lab, students have the option to round the time measurements to 0, 1, 2, or 3 decimal places.
As I played with different words I noticed that it took me longer to start the game when there were more letters to have search through to find the letter I needed, so I added a measure for how long it takes for the first click. I noticed as I was playing the game that often I missed the dot when trying to click it, so added the number of clicks as a measure. I also wanted to compare the number clicks to the number of letters to see how many times I missed, so I added the number of letters as a measure.
I was also interested in whether some games were easier/harder to play because the dots started/stayed closer together (the game randomly decides where to place the dots at the beginning of the game, more about this later….), so I added a measure for the distance between each click when a dot was hit (measured in pixels). I then noticed that in games when I was really struggling I was moving the mouse a lot around as I tried to “track” the dots, so I added a measure for the distance the mouse is moved during the game (measured in pixels).
In terms of the accuracy of the times recorded, there will be a very slight delay between the actual click and the time recorded, while the code behind the game does its calculations. I can’t notice the delay when I play, but it could be that for different devices the delay is longer (or shorter). The game plays on the “client side” so there is no need to consider internet speed or server load.
Here’s another version of the game that shows you all the current performance measures and with the time rounded to two decimal places – have a go!
Can you get better at the game?
The original version of the game will give each student a starting word for the game, randomly selected from a list of approved words. Get the students to play the game once and to write down the time. Then get them to play the game again with the same word and compare this time to their first time. Depending on the settings you have used, you might need to change the rounding of the time measurement for students to be able to see a difference (or incorporate this as part of the teaching – the need to measure time more accurately than seconds).
Get the students to keep playing the game with the same word so they can notice different kinds of variation: variation in their own times, potential decrease of times with practice, variation in how the game positions the letters of the word and how the letters move during the game. Then get the students to try out another word (click new word), again repeating the game with this new word multiple times. For example, here are my times for repeating the same word four times for four different words, represented on a line graph:
A reason why the “practice effect” is not very strong when playing this game is because even with the same word, each game is different because the starting positions and angles for each letter differ (assigned using a random process). I’ve played the game many times, and generally my time decreases between the first and second attempts of the same word for shorter words, but then the time goes back up again for subsequent attempts. I haven’t noticed much of a difference for the longer words for the times to complete the game. The weak/non-existent practice effect for longer words is helpful for exploring paired comparison experimental designs.
Most games involve randomness in the game design, so the next question could be whether the game is fair if each game is different? Does the scoring system (if it existed) need to take into account how the letters were placed at the start of the game? Or does it all just balance out?
How can you make different levels of the game?
In the experiment lab, there are lots of ways to modify the game. If you think about a simple “comparison of two independent groups” design, then students can learn as much from two versions of the game that give “different” results than two versions that give “similar” results. I’ve played the game many times during its development and there are just so many comparisons to be explored, but here are a few ideas. Of course, everything else for the game would be kept the same (same word, same dot size, speed, same instructions etc.) except for the treatment described below:
Word displayed in order vs reverse order
No movement vs slow movement
Bright red coloured background vs light grey coloured background
One word vs another word
Some of these comparisons are also related to what you are measuring for the performance e.g. I wouldn’t expect to see much of a difference between the time to first click for words displayed in order vs reverse order. This is a good thing, as students should be justifying their selection of variables 🙂 Not all words will necessary suit the type of experiment they want to conduct, which they should learn from trying out the experiment on themselves first.
It is also possible to create very different versions of the games, but the player needs to be taken into account. For example, using small dots with the highest speed will lead to rage quit! [well, if there was a quit button – the stop button is all that is on offer!] We want the game to be addictive – challenging enough for players to keep interested but not so difficult that they just give up.
How can you award points for playing the game?
You could think about awarding points for the game in terms of rewarding good playing (skill) and punishing bad playing (no skill). This links to the earlier question about how to measure performance. To demonstrate bad playing, you could set up a version of the game so that the dots are not visible (using the same colour of the dots as the background colour and letter colour), so students have to guess where to click to select the correct dot. Give it a go below:
Did you give up? It took me 84 clicks 🙂 Clearly skill is involved when you play the game and “random” clicking is probably not going to help you click the correct dot faster. So it could be that the points are initially awarded based on the time to complete the game, but points are then taken off for extra clicks. To award points based on the time to complete the game needs a way to “baseline” the game to take into account different words. So the students will need to explore relationships between the performance measures e.g. the number of letters of the word vs the time to complete the activity.
Also, if two performance measures appear to have a relationship, than it might not make sense to use both variables to determine points (e.g. time to first click and time to complete the game). Each player brings their own level of skill and practice with the game, but can we use two of the performance measures to find out more about how people play the game? I think there are a lot of good reasons to explore the relationships between the performance measures…..
More about the game…..
This is the first stage of an online game I’m developing, built off code from this website with my own additions and improvements. There are lots of similar games out there involving balls – here are just a couple:
If you (or your students) are interested in the design of the game itself, just look at the page source of this page to see the code. There is a fair bit of logic and mathematics involved (e.g. trigonometry, co-ordinate geometry, measurement). I’ve set the words used for the game to a fixed “approved” list so students can’t create games with dodgy words, even if they try to hack the link used to access a different version of the game 🙂