Help I am lost in the forest of Probability!

[shl]

I am hoping someone can help me. I have never used a site like this, hopefully I am doing this correctly.
I can not seem to wrap my head around probability!

I have two problems that I do not know where to begin!

1. A hay fever medication claims that symptoms dissapear within 36 hours of taking the medication for 90% of the people.
If a random sample of 275 peiole on the medication found that 232 had relief after 36 hours, is this consistent with the claim at the 3 level? (There is a funny symbol behind the 3 it looks like a scripted O)

2. Out of 2 million hay fever sufferers in Canada, 78% are allergic to ragweed. If a random sample of 7 hay fever sufferers is selected,
a) what is the probability that 3 are allergic to ragweed?
b) what is the probability that 1 is allergic to ragweed?

Thanks in advance for any assistance I receive. [/quote][/list][/code]

 

[Trebor]

Firstly, does that funny scripted O symbol look like a percentage sign? It is probably referring to the significance level.

Secondly, both questions use binomial distributions, but because of the large data set for the first question you will need to use the Normal approximation. Also, the first is a 2-tailed hypothesis test.

Do you know how to use binomial distributions? If not, you will need to go over it with your tutor, as it is necessary to answer these questions.