Answer:
a ) 0.9
Expected number of bower-birds that have bowers featuring reflective decor
     μ = 0.9
Step-by-step explanation:
Explanation:-
Given Sample size 'n' = 20
Given data A population consists of twenty bower-birds, six of which have bowers featuring reflective decor.
probability of success
             [tex]p = \frac{x}{n} = \frac{6}{20} =0.3[/tex]
Given  three of the bower-birds are randomly sampled with replacement from this population.
So we will choose sample size 'n'= 3
Let 'X' be the random variable in binomial distribution
Expected number of bower-birds that have bowers featuring reflective decor
            μ = n p
              = 3 × 0.3
              =0.9
conclusion:-
Expected number of bower-birds that have bowers featuring reflective decor
     μ = 0.9
