Please help-- in a hurry and would really appreciate it!! Thanks in advance :) F
ID: 3055145 • Letter: P
Question
Please help-- in a hurry and would really appreciate it!!
Thanks in advance :)
Explanation / Answer
From the information 53% of the flowers of the rewardless orchid are yellow and remaining flowers are purple.
percentage of purple flower =47%
i) P ( Selected flower would it be purple) = 1 -0.53 = 0.47
ii) n = number of flowers selected for sample = 6
X = number of flowers would be purple.
p = probability of flower would it be purple = 0.53
Hence the distribution of random variable X is binomial with n =6 and p =0.47
P ( At least 4 would be purple) = P( X >= 4) = 1- P( X <=3)
P( X<=3) which is cumulative probability at X=3.
by using excel BIN0MDIST(number_s,trials,probability_s,cumulative)
P( X <=3) = BINOMDIST(3,6,0.47,1) = 0.710684
P ( At least 4 would be purple) = P( X >= 4) = 1- 0.710684 = 0.289316
iii) number of trials = n = 260
P(150 or more of the orchid are purple) = P( X >=150) = P( X <= 149)
since number of trials are large . By using binomial approximation of binomial distribution.
P( X <=149) = P( Z < (149 +1/2 -260*0.47) / sqrt(260*047*0.53))
where Z ~ N(0,1) E(Z) =mean = 0 and S.D(Z) =standard deviation = 1
= P(Z <= 3.3922) which is cumulative probability at Z = 3.3922
By using Excel Function NORMDIST(X ,mean, standard_dev,cumulative)
P(Z <= 3.3922) = NORMDIST(3.3922,0,1,true) = 0.9996
P(150 or more of the orchid are purple) = 0.9996
or
By using normal probability table
P(Z <= 3.3922) = 1 - P( Z >3.3922)
from normal probability table
P( Z >3.3922)=0.0003
P(Z <= 3.3922) = 1-.0003 = 0.9997