Answer :
Answer:
the probability that this employee belongs to group I is 0.2118
Step-by-step explanation:
Given the data in the question;
P( group 1 ) = 0.20
P( group 11 ) = 0.60
P( group 111 ) = 0.20
now
[tex]P( \frac{certified}{Group1} )[/tex] = 0.10
[tex]P( \frac{Not-certified}{Group1} )[/tex] = 0.90
[tex]P( \frac{certified}{Group11} )[/tex] = 0.20
[tex]P( \frac{Not-certified}{Group11} )[/tex] = 0.80
[tex]P( \frac{certified}{Group111} )[/tex] = 0.05
[tex]P( \frac{Not-certified}{Group111} )[/tex] = 0.95
so
[tex]P( \frac{group1}{Not-certisfied} )[/tex] = [ [tex]P( \frac{Not-certified}{Group1} )[/tex] × P( group 1 ) ] / [ [tex]P( \frac{Not-certified}{Group1} )[/tex] × P( group 1 ) + [tex]P( \frac{Not-certified}{Group11} )[/tex] × P( group 11 ) + [tex]P( \frac{Not-certified}{Group111} )[/tex] × P( group 111 ) ]
we substitute
[tex]P( \frac{group1}{Not-certisfied} )[/tex] = [ 0.90×0.20 ] / [ 0.90×0.20 + 0.80×0.60 + 0.95×0.20
[tex]P( \frac{group1}{Not-certisfied} )[/tex] = 0.18 / [ 0.18 + 0.48 + 0.19 ]
[tex]P( \frac{group1}{Not-certisfied} )[/tex] = 0.18 / 0.85
[tex]P( \frac{group1}{Not-certisfied} )[/tex] = 0.2118
Therefore, the probability that this employee belongs to group I is 0.2118