From the given data, the following Table is calculated:
|
Upgrade to Windows 10 |
No change from Windows 7 |
No preferences |
Total |
| Secretary |
0.20X0.55=0.11 |
0.20X0.17=0.034 |
0.20X0.28=0.056 |
0.20 |
| Not a secretary |
0.80X0.39=0.312 |
0.80X0.55=0.44 |
0.80X0.06=0.048 |
0.80 |
| Total |
0.422 |
0.474 |
0.104 |
1.00 |
P(Not a secretary/ Preference) = P(Not a secretary AND
Preference)/ P(Preference)
                                         Â
= 0.752/0.896
                                         Â
= 0.839
So,
Answer is:
0.839
