Question

Fifteen percent of new residential central air conditioning units installed by a supplier need additional adjustments requiring a service call. Assume that a recent sample of seven such units constitutes a binomial process. Interest centers on X, the number of units among these seven that need additional adjustments. The mean and variance of X are, respectively

Answer 1

Answer:

The mean will be "1.05".

Step-by-step explanation:

According to the question, the values are:

p = 15%

or,

  = 0.15

q = 1-p

  = 1-0.15

  = 0.85

n = 7

As we know,

⇒ $P(X=x)=n_C_x(q)^{n-x}(p)^x$

Now,

The mean will be:

⇒ $\mu = np$

       $=7\times 0.15$

       $=1.05$