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# Stats help watch

1. Hi,
I'm having trouble with my stats homework. I didn't do statistics at a level so I'm really clueless at this.

In London in April, the probability that it rains on any particular day is 0.3. Calculate the probability that:
(i) It rains on each of the first 3 days in April. (State any assumptions you have made in order to carry out your calculation.)
(ii) It rains on the first day and is dry for the next 3 days.

2. (Original post by Blahblahblah96)
^
i) consider the fact that for three days, it rains. The probability of it raining on each day is 0.3. So the probability of it raining on all three days is...

(remember that you multiply probabilities in an AND scenario).

ii) what's the probability of it NOT raining? Take this, and consider another AND situation where it doesn't rain on day 1, and does for three days.

Solution in spoiler (try to give it a go first though).
Spoiler:
Show
Let the probability that it rains = R = 0.3
Therefore the probability it doesn't rain = R' = 1 - 0.3 = 0.7

i) P = RRR = 0.33 = 0.027

ii) P = R'RRR = 0.7 x 0.33 = 0.0189

Hope I helped

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