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biostats - adrenaline2176
#81
Hey cansome one explain me what this rule of occurence of the disease means?

I was thinkings its given in the Q...sensitivity=95%
But why r u considering 'NOT detecting the disease = 0.95 or 95%'

I didnt get...and kind of lost with ur explanation also adrenaline...guess my brain stopped...to think

Sorry...
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#82
Yeah do...I wanted to add that A cannot be equal to B if the brackets are applied elsewhere.

(1-0.05)* 8 = 0.95*8 =! 1-(0.05*8) (=! not equal to)

Now..for a qucik math thing.... factorials

5! = 5x4x3x2x1 and 3! = 3x2x1

so 5C3 = 5!/3!*2! = 5x4x3!/(3!x2) = 5x4/2 = 10


Why is the above formula useful?..well if the q asks u..whats the probability that 3 individuals have a positive result?

P(X=3) = 8!/3!5! * 0.05^3 * 0.95^5
= (8x7x6x5!/ 3x2 * 5!) * 0.05^3 *0.95^5
= 56* 0.05^3 *0.95^5


Good luck,
Reply
#83
Yeah do...I wanted to add that A cannot be equal to B if the brackets are applied elsewhere.

(1-0.05)* 8 = 0.95*8 =! 1-(0.05*8) (=! not equal to)

Now..for a qucik math thing.... factorials

5! = 5x4x3x2x1 and 3! = 3x2x1

so 5C3 = 5!/3!*2! = 5x4x3!/(3!x2) = 5x4/2 = 10


Why is the above formula useful?..well if the q asks u..whats the probability that 3 individuals have a positive result?

P(X=3) = 8!/3!5! * 0.05^3 * 0.95^5
= (8x7x6x5!/ 3x2 * 5!) * 0.05^3 *0.95^5
= 56* 0.05^3 *0.95^5


Good luck,
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#84
For nautilus,

RULE IN...... sensitivity
RULE OUT...specificity
the specificity is given in the q
hope it helps Smile
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#85
For nautilus,

RULE IN...... sensitivity
RULE OUT...specificity
the specificity is given in the q
hope it helps Smile
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#86
ohh ur doing the joint probability thing... first of all the explanation and the formula went jara bumper! but will work on it...its sowly sinkin in... thank u!
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#87
ohh ur doing the joint probability thing... first of all the explanation and the formula went jara bumper! but will work on it...its sowly sinkin in... thank u!
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#88
Hey Nautilius...its "Rule out"...not rule of. I corrected that mistake in doctoria's post. Sorry for the misunderstanding.

Doctoria -I have a silly Q ..."rule of"... is that "rule out", Adrenaline ?
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#89
Hey Nautilius...its "Rule out"...not rule of. I corrected that mistake in doctoria's post. Sorry for the misunderstanding.

Doctoria -I have a silly Q ..."rule of"... is that "rule out", Adrenaline ?
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#90
Hey pash...this type of prob is called the tree diagram. Where u first mobe from one person the next.

Eg. 1.....D+/D- ----2----D+/ D- ......3....D+/ D-...etc.

U write the prob of each branch eg D+ = 0.05, D- = 0.95 and in the end multiply them.

So inorder for no one to be have a positive result.

D-......D-......D-........D-.......D-.........D-..........D-.........D- = 0.95^8


I hope this is easy to understnad Smile hey CD..where r u?
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