What is the probability of it raining, P(B), if it has started snowing? Report P(B), given that it has already started snowing as a percent.

MATLAB: An Introduction with Applications
6th Edition
ISBN:9781119256830
Author:Amos Gilat
Publisher:Amos Gilat
Chapter1: Starting With Matlab
Section: Chapter Questions
Problem 1P
icon
Related questions
Question

5

Let's say the weatherwoman says the chance of rain is 60%
and the chance of snow is 50%. What's the chance of rain OR snow? If you just add, you get:
P(rain or snow) = P(rain) + P(snow) = 110%
Probabilities over 100% are meaningless. So right off the bat you know something is wrong.
How about the chance of rain AND snow? The Law of AND would say
P(rain and snow) = P(rain) * P(snow) = 30%
But we all know that rain often turns into snow and snow turns into rain, so these two events are not independent
either and we can't use the multiplication rule.
In fact, we really can't say ANYTHING about rain combined or not combined with snow. We can't add rain OR snow,
but we also can't multiply to get rain AND snow. The two events aren't mutually exclusive, and they aren't
independent. Neither law does us any good.
In this case what you would need to know is the conditional probability in order to determine the probability of rain, if
it is already snowing, or snowing, if it is already raining.
Conditional Probabilities are usually written as P(A|B) and read aloud as "The Probability of
A, given B."
If there is a 60% chance of snow, and a 17% chance of rain, if it is already snowing, then we
can let snow be Event A, and rain be event B. Therefore, P(A) = 60, and P(B|A) = 17.
%3D
To find the chance of it raining, after it has started snowing, we can multiply P(A)*P(B|A) to
find the answer.
What is the probability of it raining, P(B), if it has started snowing? Report P(B), given that it
has already started snowing as a percent.
Round to the nearest whole percent (for example, 30 rather than 30.4).
Transcribed Image Text:Let's say the weatherwoman says the chance of rain is 60% and the chance of snow is 50%. What's the chance of rain OR snow? If you just add, you get: P(rain or snow) = P(rain) + P(snow) = 110% Probabilities over 100% are meaningless. So right off the bat you know something is wrong. How about the chance of rain AND snow? The Law of AND would say P(rain and snow) = P(rain) * P(snow) = 30% But we all know that rain often turns into snow and snow turns into rain, so these two events are not independent either and we can't use the multiplication rule. In fact, we really can't say ANYTHING about rain combined or not combined with snow. We can't add rain OR snow, but we also can't multiply to get rain AND snow. The two events aren't mutually exclusive, and they aren't independent. Neither law does us any good. In this case what you would need to know is the conditional probability in order to determine the probability of rain, if it is already snowing, or snowing, if it is already raining. Conditional Probabilities are usually written as P(A|B) and read aloud as "The Probability of A, given B." If there is a 60% chance of snow, and a 17% chance of rain, if it is already snowing, then we can let snow be Event A, and rain be event B. Therefore, P(A) = 60, and P(B|A) = 17. %3D To find the chance of it raining, after it has started snowing, we can multiply P(A)*P(B|A) to find the answer. What is the probability of it raining, P(B), if it has started snowing? Report P(B), given that it has already started snowing as a percent. Round to the nearest whole percent (for example, 30 rather than 30.4).
Expert Solution
trending now

Trending now

This is a popular solution!

steps

Step by step

Solved in 2 steps

Blurred answer
Recommended textbooks for you
MATLAB: An Introduction with Applications
MATLAB: An Introduction with Applications
Statistics
ISBN:
9781119256830
Author:
Amos Gilat
Publisher:
John Wiley & Sons Inc
Probability and Statistics for Engineering and th…
Probability and Statistics for Engineering and th…
Statistics
ISBN:
9781305251809
Author:
Jay L. Devore
Publisher:
Cengage Learning
Statistics for The Behavioral Sciences (MindTap C…
Statistics for The Behavioral Sciences (MindTap C…
Statistics
ISBN:
9781305504912
Author:
Frederick J Gravetter, Larry B. Wallnau
Publisher:
Cengage Learning
Elementary Statistics: Picturing the World (7th E…
Elementary Statistics: Picturing the World (7th E…
Statistics
ISBN:
9780134683416
Author:
Ron Larson, Betsy Farber
Publisher:
PEARSON
The Basic Practice of Statistics
The Basic Practice of Statistics
Statistics
ISBN:
9781319042578
Author:
David S. Moore, William I. Notz, Michael A. Fligner
Publisher:
W. H. Freeman
Introduction to the Practice of Statistics
Introduction to the Practice of Statistics
Statistics
ISBN:
9781319013387
Author:
David S. Moore, George P. McCabe, Bruce A. Craig
Publisher:
W. H. Freeman