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Joint Entrance Examination
Mathematics
Probability
Question 248
Question 248 of 417
Easy
MCQ
Mean and variance of a binomial variate
X
X
X
are 2 and 1. Find
P
(
X
≥
1
)
P(X\ge1)
P
(
X
≥
1
)
.
A
9
/
16
9/16
9/16
B
3
/
4
3/4
3/4
C
1
/
16
1/16
1/16
D
15
/
16
15/16
15/16
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Official solution
n
p
=
2
,
n
p
q
=
1
⇒
q
=
p
=
1
2
,
n
=
4
np=2,npq=1\Rightarrow q=p=\dfrac12,n=4
n
p
=
2
,
n
pq
=
1
⇒
q
=
p
=
2
1
,
n
=
4
. \[P(X\ge1) = 1-\left(\frac12\right)^4=\frac{15}{16}\]
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