5.34+6.89= 12 That is what I got
Answer:
A sample of at least 545 adults is needed.
Step-by-step explanation:
In a sample with a number n of people surveyed with a probability of a success of
, and a confidence level of
, we have the following confidence interval of proportions.
In which
z is the zscore that has a pvalue of
.
For this problem, we have that:

The margin of error is:
95% confidence level
So
, z is the value of Z that has a pvalue of
, so
.
If he wishes to be 95% confident that his estimate contains the population proportion, how large a sample will be necessary?
We need a sample of at least n.
n is found when M = 0.03. So




Rounding up
A sample of at least 545 adults is needed.
Answer:
the probability that 11 adults are satisfied is 0.115 (11.5%)
Step-by-step explanation:
since the result of each adult is independent of others , then since the adults are selected at random , the random variable X= number of adults who are satisfied , has a binomial probability distribution , where
P(X=x) = n!/[(n-x)!*x!] * p^x * (1-p)^(n-x)
where
n= sample size = 20
p= probability of any adult to be satisfied with the job of airlines = 0.65
x = number of adults who are satisfied
P(X=x) = probability that x adults are satisfied
then for x= 11 , we have
P(X=11) = 20!/[(20-11)!*11!] * 0.65^11 * (1-0.65)^(20-11) = 0.115 (11.5%)
then the probability that 11 adults are satisfied is 0.115 (11.5%)
'is' in mathematics means equal
'of' in mathematics means multiplication
55% of 20 is 11.