It is important to note that all the information's required are already given in the question
Probability that a day will be hot = 0.15 + 0.10
= 0.25
Probability that a day will be sunny = 0.15 + 0.30 + 0.10
= 0.55
Adding the above two probabilities, we get = 0.25 + 0.55
= 0.80
Now
Probability that a day will be both hot and sunny = 0.15
So
Probability that a day was hot or sunny = 0.80 - 0.15
= 0.65
I hope the procedure is clear enough for you to understand.
In statistics, the amount of degrees of freedom is
the quantity of values in the final computation of a statistic that are free to
differ. In this case, you can get the answer by adding the number of bags
and subtracting 1.
So in computation, this would look like: 3 + 2 + 1 + 2 - 1 =
7
Therefore, 7 is the degrees of freedom.