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Stats question help

Hi can someone please help me with q4d and explain it thanks ImageUploadedByStudent Room1465919068.780518.jpg


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Reply 1
Hey so we know the chance of passing the test the first time is P and the chance of passing the second time is (P-0.2).
In order to attempt the test the second time you need to fail the first time. So to pass the second time you must fail first time and pass second time which gives => (1-p)(p-0.2).
Also you know that you can pass the first time and wont have to take the test the second time so add p to that. Lastly 95% of students are expected to pass so = 0.95 at the end.
(1-p)(p-0.2)+p=0.95
next just expand and you get the answer
(edited 7 years ago)
Original post by Icyytea
Hey so we know the chance of passing the test the first time is P and the chance of passing the second time is (P-0.2).
In order to attempt the test the second time you need to fail the first time. So to pass the second time you must fail first time and pass second time which gives => (1-p)(p-0.2).
Also you know that you can pass the first time and wont have to take the test the second time so add p to that. Lastly 95% of students are expected to pass so = 0.95 at the end.
(1-p)(p-0.2)+p=0.95
next just expand and you get the answer


THANK YOU that is so easy


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