Open the Fair Coins Starter File, which defines coin1, coin2, and coin3. Click "Run". You can flip each coin by evaluating flip(coin1) in the Interactions Area (repeat for coins 2 and 3). One of these coins is fair, one will land on "heads" 75% of the time, and one will land on "heads" 90% of the time. Which one is which?
1 In the table below, record five flips of each coin and the number of "heads" you saw. Then convert that number into a percentage. Finally, write a "Y" or "N" depending on whether you think each coin is fair based on your sample.
| Sample | coin1 | coin2 | coin3 |
|---|---|---|---|
1 |
|||
2 |
|||
3 |
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4 |
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5 |
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#heads |
/5 |
/5 |
/5 |
% heads |
% |
% |
% |
fair? |
2 In the table below, record 15 more flips of each coin and the number of "heads" you saw. Then convert that number into a percentage. Finally, write a "Y" or "N" depending on whether you think each coin is fair based on your sample.
| Sample | coin1 | coin2 | coin3 |
|---|---|---|---|
6 |
|||
7 |
|||
8 |
|||
9 |
|||
10 |
|||
11 |
|||
12 |
|||
13 |
|||
14 |
|||
15 |
|||
16 |
|||
17 |
|||
18 |
|||
19 |
|||
20 |
|||
#heads |
/20 |
/20 |
/20 |
% heads |
% |
% |
% |
fair? |
3 Which weighted coin did you identify first: fair, 75%, or 90%?
4 Why was that coin the easiest to find?
These materials were developed partly through support of the National Science Foundation, (awards 1042210, 1535276, 1648684, 1738598, 2031479, and 1501927). 
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