In: Math
Assume that x is a binomial random variable with n = 100 and p =
0.40. Use a normal
approximation (BINOMIAL APPROACH) to find the
following: **please show all work**
c. P(x ≥ 38) d. P(x = 45) e. P(x > 45) f. P(x < 45)
Solution :
Given that,
p = 0.40
q = 1 - p =1-0.40=0.60
n = 100
Using binomial distribution,
= n * p = 100*0.40=40
=
n * p * q =
100*0.40*0.60=4.8990
Using continuity correction ,
(C)P(x ≥ 38 ) = 1 - P(x <37.5)
= 1 - P((x -
) /
< (37.5 - 40) /4.8990 )
= 1 - P(z <-0.51 )
= 1 - 0.3050
=0.6950
(d)Using continuity correction ,
P(x = 45)= P[(44.5 - 40)/4.8990 ) < (x -
) /
< (45.5 - 40) /4.8990 ]
= P( 0.92< z < 1.12)
= P(z <1.12 ) - P(z <0.92 )
=0.8686 - 0.8212
=0.0474
(E)P(x >45 ) = 1 - P(x <45)
= 1 - P((x -
) /
< (45.5 - 40) /4.8990 )
= 1 - P(z <1.12 )
= 1 - 0.8686
=0.1314
(F)P(x <45 )= P((x -
) /
< (44.5 - 40) /4.8990 )
= P(z <0.92 )
=0.8212