The musical pause. Anna Castillo & Macarena García sing for Whitney Houston
Act 1
Possible questions:
- What is the probability that someone, choosen randomly, guess the retake of the song?
- What is the error to try to guess the music retake?
- How does this error distribute? Is it normal distribution or something else?
Act 2
- The Whitney Houston’s “I will always love you” video
- The Roxette’s “The look” video which has also a sound pause
Development of the activity
- The students sit in pairs
- One student take a pencil and another a mobile phone. The student with the mobile phone needs the camera and chronometer applications.
- Teacher puts the video on without the image, just the sound. Meanwhile the student with the camera records the other student who, when she wants, hits the table with a pencil (or claps her hands).
- Later, with chronometer application students see the time between sound pause and student pencil hit
- Students could measure many times this interval and make the mean.
- Students see that error varies with the help of these means.
- We could answer these questions:
- Is it difficult to guess exactly the sound retake? What precision is necessary?
- If we took this experiment with many people, what would be the mean error?
- What is the variation between the moment when someone guess the retake and the real one?
- What is the probability of one person just have an error of 0.5 seconds from the real retake?
Notes
- A related activity could be counting up to 30 and see what would be the deviation respect to 30 real seconds
- On one hand, this activity could use to introduce the concepts of statistical sample and statistical population. On the other hand, to introduce the concept of experimental probability (a probability which needs to get data from outside to be calculated)
- It seems that the maximum precision is about half milliseconds.
Classroom implementation
The 2018-2019 season I implemented this activity in classroom for the first time:
- Just after implement theorical probability activities, I introduced this activity.
- We saw the Hormiguero video and then the question to answer was “What is the probability that one person guess when the sound returns to the song?”. We saw the nececessity to take an statistical sample (that classroom). I so explained the difference between sample and population.
- By pairs, students recorded partners when song was in the background.
- After that, students saw the time between sound silence beginning and their clap. We made that at least 3 times to dilute errors.
- Then students saw the time between sound silence beginning and the real sound retake.
- We did the same Roxette song.
- To calculate the asking probability, we calculated the percentage between their gap and the real gap of the song. We convene 5% or less is OK and more is a mistake. By this way, we counted the number of persons in the interval [0%, 95%) and [95%, 105%) and more than 105%.
About this document
The author of this work is Xavier Bordoy which is distributed under CC-BY-NC-SA 4.0 license. Its date of creations is 2019-05-13.
The original video belongs to “El hormiguero”: “Anna Castillo y Macarena García cantan por Whitney Houston en ‘El Hormiguero 3.0’” from Antena 3 (Sep 25th, 2017).
The work has keywords: “statistical population”, “statistical sample”, “arithmetic mean”, “error”, “precision”, “experimental probability”, “normal distribution”, “statistical distribution”, “probability”, “statistics”, “when”.