Play to Learn
Percentile Rank
A percentile rank indicates the percentage of the population a person scored above. A percentile ranking is written as a number, with a small "th" at the top right. Mariana's percentile for running speed among girls her age is 77th. This means that her running time is faster than 77% of the other girls.
Proportion from the Left Tail
For percentile rankings, think of the proportion of scores smaller than a specified value. On a number line, this means all scores to the left of the specified value. Doug's score was a 23. To determine his percentile ranking, we would shade in all of the scores to the left (i.e., that are lower), as they are smaller than a score of 23. Doug scored above .25 of his group. We multiply the .25 by 100, and now we have the percentage of 25%. To indicate that Doug scored above 25% of his group, we would state that his percentile ranking is 25th.
Proportion for the Right Tail
Sometimes the focus is on the "top" performers. For example, the CSUs aim to accept the top .25 of the graduating high school seniors. Looking at a normal distribution, we would see it shaded inward from the right tail.
Perceptual Skill
Develop your basic understanding of proportions and the normal distribution. The proportions in this activity will either start in the left or the right tail.
Notice the z score along the x axis. A proportion that starts in the tail and concludes at the z score of zero represents half of the population. A proportion that starts in the left tail an concludes at the z score of -2 represents approximately 2.5% of the population.
Additional Resource
Normal Probability Distribution Graph Interactive
Click Start to play. You will get practice with making 30 decisions.
During a decision trial, press the 'f' key to select the option on the left and the 'j' key to select the option on the right.
If visibility is an issue, the Voice System can be turned on for this activity by pressing the Tab key (after clicking on the activity and waiting for it to load). Pressing the left and right arrows adjusts the rate of speech. The 'Z' key will interrupt the Voice System. Pressing the period turns the voice system off. During a decision trial, the keys 'e' and 'i' may be pressed for a verbal description of the left and right choices, respectively. Unlimited decision time is allowed when the Voice System is on. Performance of the Voice System can be impacted by the browser/system/device used.
If the decision time (before the correct answer is shown) is too quick, then you may re-start the game (e.g., by refreshing the browser tab). From the game menu, click the 'Accommodations' button, and then enter the code "#17" for unlimited decision time. Click the 'Continue' button to return back to the game menu. The student's passcode can be combined with an accessibility code (e.g., '4524#17' to indicate that the student's passcode is 4524, using the accessibility code 17).
Alternatively, to switch to unlimited decision time during game play, using a physical keyboard, press the left bracket '[' key. Doing so will affect the next decision trial. Press the right bracket ']' to return back to the specified decision time.
Enjoy the game, but would like to change it up? From the game menu, click the 'Accommodations' button. In the Accommodations dialog box, enter a code to change how the game functions:
Minimum number of decision trials: Use the code 0## (replacing the two digit '##' with the number of trials desired). For example, the code 009 would result in a minimum of 9 decision trials, whereas the code 060 would result in a minimum of 60 decision trials.
Decision time: 2## (replacing the two digits '##' with the number of seconds available to make a decision). For example, the code 205 would result in an allowed decision time of up to 5 seconds. The code 212 would result in an allowed decision time of up to 12 seconds.
The code consists entirely of digits. After entering a code in the Accommodations dialog , press the 'Continue' button to return back to the game menu. You can also combine codes, such as '020204' to indicate 20 decision trials ('020') and a decision time of four seconds ('204').
Finally, the student's passcode can be combined with codes to modify game play (e.g., '4524-015205' to indicate that the student's passcode is 4524, with '015' indicating a minimum of 15 trials and '205' indicating that up to five seconds is allowed for each decision before the correct answer is shown.
To view more options for modifying game play, visit the Play to Learn modifications page.
Instructors can provide their students with a four digit passcode to enter at the start of the game. The student would click the 'Accommodations' button, and in the Accommodations dialog box provide the passcode, and then press the 'Continue' button to return back to the game menu.
At the end of game play, a completion code will be provided for a successfully played game (i.e., performance reached the specified threshold; e.g., 85%). The student would enter the completion code as their answer to a quiz question.
Use of the accessibility options will modify the completion code (by +/- 2). Modifying game play (e.g., changing the number of decision trials) will result in an entirely different completion code. Instructors can choose to allow accommodations by accepting a completion code that comes within +/- 2 of the expected completion code value. Those students whose quiz question is graded correctly, but where the completion code is different than the expected result, used an accommodation.
The use of Completion codes represents one way to recognize students for successful game play.