MATH 5035, Dr. Beckmann, Thursday March 16
Probability activities
1) You have a spinner with 10 identical sectors; 7 are blue and 3 are yellow. What is the
(theoretical) probability of spinning blue? Why?
2) Go to either http://nlvm.usu.edu/en/nav/frames_asid_186_g_1_t_1.html?open=activities
or to https://illuminations.nctm.org/adjustablespinner/
and make a spinner that has 10 identical sectors: 7 blue and 3 yellow. Try it out!
For each of the following numbers, spin the spinner that many times, record the number of
blue spins and the percentage of the spins that were blue.
Be sure to reset your spinner when you do a new number of spins.
# spins:
10
50
100
500
1000
5000
# blue:
% blue:
What do you notice?
Repeat what you just did! Be sure to reset your spinner when you do a new number of spins.
# spins:
10
50
100
500
1000
5000
# blue:
% blue:
What do you notice?
3) If you were to spin the spinner 3000 times, how many times would you expect it to land on
blue? Explain!
4) If you were to spin the spinner X times, how many times would you expect it to land on blue?
Explain!
5) If you wanted the spinner to land on blue 1400 times, how many times would you expect to
have to spin it? Explain!
6) Explain your answers to the following:
(a) Let’s say you’ll win a prize if between 60% and 80% of your spins land on blue. Is it
better to spin 20 times or 200 times or 2000 times or does it not matter?
(b) Let’s say you’ll win a prize if between 40% and 60% of your spins land on blue. Is it
better to spin 20 times or 200 times or 2000 times does it not matter?
(c) Let’s say you’ll win a prize if less than 60% of your spins land on blue. Is it better to
spin 20 times or 200 times or 2000 times or does it not matter?