Total outcomes when rolling a pair of dice = 36
Total ways to get sum 7= 6
P(7) = 6/36 = 1/6
So, P(I = 1) = 1/6
P(I = 0) = 1 - 1/6 = 5/6
| I | 0 | 1 | Total |
| P | 5/6 | 1/6 | 1 |
| I*P | 0 | 1/6 | 1/6 |
| I^2 *P | 0 | 1/6 | 1/6 |

Hence 5/36 is the Variance of I.
Please comment if any doubt. Thank you.
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