The average age of residents in a large residential retirement community is 69 years with standard deviation 5.8 years The probability that the average age, xbar of the 100 residents selected is less than 68.5 years is:

The probability that the average  of the 100 residents selected is less than 68.5 years is

P( x⁻< 68.5) = 0.1949

Step-by-step explanation:

Step(i):-

Given mean of the Population = 69

Given standard deviation of the Population = 5.8 years

Let x⁻ be the average random variable in normal distribution

Given     x⁻  = 68.5

By using

              Z   = -0.862

Step(ii):-

The probability that the average  of the 100 residents selected is less than 68.5 years is

P( x⁻< 68.5) = P( z <-0.862)

                   =  1- P( Z >- 0.862)

                   =   1 - ( 0.5 + A(-0.862)

                  =    0.5 - A( 0.862)              (  A( -Z) = A(Z))

                  =   0.5 - 0.3051

                 =  0.1949

Conclusion:-

The percentage of the probability that the average  of the 100 residents selected is less than 68.5 years  = 19 %

1. sometimes

2.   never

3   .08c = 7.50+.05c   250 pages

step-by-step explanation:

1.   sometimes

the theoretical probability of rolling a 1 is 1/6.   perhaps you got really lucky and never rolled a 1   in those 60 times.   your experimental probability is 0.   or perhaps you rolled a 1   20 times.   your experimental probability is 20/60 is 1/3.     it really just depends on how you rolled in that experiment.

2.   never

the probability of the event occurring is 1.   that is being 100 % sure it will happen.   that is the maximum amount of confidence we have.

3.   no customer card cost:   .08 times number of pages

customer card cost:   7.50 + .05 times number of pages

we want to find when it costs the same amount, so we will set these equal

let c = number of pages

.08c = 7.50+.05c

subtract .05c from each side

.08c-.05c = 7.5+.05c-.05c

.03c=7.5

divide each side by .03

.03c/.03 = 7.5/03

c =250  

the cost is the same at 250 pages

inverse property is the answer

step-by-step explanation: