The Student Room Group

Probability

How would you do this?
prob.PNG
(edited 1 year ago)
Use independence to get a quadratic in p repreenting the joint probability, then get the corresponding q(s) to sum to 1.
(edited 1 year ago)
Reply 2
Original post by mqb2766
Use independence to get a quadratic in p repreenting the joint probability, then get the corresponding q(s) to sum to 1.


Thanks, i get it now
Reply 3
I also need help with this:

A batch contains n components which have been randomly selected.
The probability that no components are faulty in batches of this size is 0.2957 to 4
decimal places.
(iii) Find the value of n.
Original post by Dell PC 2
I also need help with this:

A batch contains n components which have been randomly selected.
The probability that no components are faulty in batches of this size is 0.2957 to 4
decimal places.
(iii) Find the value of n.

I need help as well, as youve missed out important info. 3% are faulty, so p of being not faulty is 0.97, so using the usual binomial or independent components or ...
0.97^n = 0.2957
Reply 5
Original post by mqb2766
I need help as well, as youve missed out important info. 3% are faulty, so p of being not faulty is 0.97, so using the usual binomial or independent components or ...
0.97^n = 0.2957


Thank you, should the answer be 40?
Reply 6
A die is biased so that the probability of obtaining a 3 is p. When the die is thrown 4 times the
probability that there is at least one three is 0.9375. Find the value of p.

i keep getting p=0.5 but the ans is p=0.825
IMG_20230527_200607.jpg

Spoiler

(edited 1 year ago)
Original post by Dell PC 2
A die is biased so that the probability of obtaining a 3 is p. When the die is thrown 4 times the
probability that there is at least one three is 0.9375. Find the value of p.

i keep getting p=0.5 but the ans is p=0.825
IMG_20230527_200607.jpg

Spoiler



I agree that corresponds to p=1/2 as 1/2^4=1/16=0.0625
Reply 8
Original post by mqb2766
I agree that corresponds to p=1/2 as 1/2^4=1/16=0.0625


Thank you so much for helping me with these questions :biggrin:

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