# chance of rain , probability

• Jul 30th 2009, 09:56 AM
jickjoker
chance of rain , probability
can anyone help with this?

chance of rain

the weather report claims that the chance of rain for certain days
next week are

Monday: 50% chance of rain
Tuesday: 20% chance of rain
Wednesday: 30% chance of rain
Thursday: 30% chance of rain
Friday: 10% chance of rain

what is the chance of rain
for the entire week as a whole ?

tx (Angry)
• Jul 30th 2009, 10:28 AM
Twig
Hi

The chance of not raining is

$0.5 \cdot 0.8 \cdot 0.7 \cdot 0.7 \cdot 0.9 =0.1764$

The complement to the event "it is not raining" is "it is raining".

A="It is not raining".

So $P(A^{C})=1-0.1764= 0.8236$
• Jul 30th 2009, 12:55 PM
Unenlightened
Quote:

Originally Posted by jickjoker
can anyone help with this?

chance of rain

the weather report claims that the chance of rain for certain days
next week are

Monday: 50% chance of rain
Tuesday: 20% chance of rain
Wednesday: 30% chance of rain
Thursday: 30% chance of rain
Friday: 10% chance of rain

what is the chance of rain
for the entire week as a whole ?

tx (Angry)

Do you mean raining every day during the week?
Or at least once during the whole week?

If it's the former it's just the product of the probabilities for each given day.

If it's the latter, think of the probability of something happening "at least once", as 1 - Probability of it not happening at all...