What is the probability of selecting a seventh-grader from a school that has 250 sixth-graders, 225 seventh-graders, and 275 eig
1 answer:
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Answer:
The minimum sample size required to create the specified confidence interval is 2229.
Step-by-step explanation:
We have that to find our level, that is the subtraction of 1 by the confidence interval divided by 2. So:
Now, we have to find z in the Ztable as such z has a pvalue of .
So it is z with a pvalue of , so
Now, find the margin of error M as such
In which is the standard deviation of the population and n is the size of the sample.
What is the minimum sample size required to create the specified confidence interval
This is n when
Rounding up
The minimum sample size required to create the specified confidence interval is 2229.
Answer:
The mean number of adults who would have bank savings accounts is 32.
Step-by-step explanation:
For each adult surveyed, there are only two possible outcomes. Either they have bank savings accounts, or they do not. So we use the binomial probability distribution to solve this problem.
Binomial probability distribution
Probability of exactly x sucesses on n repeated trials, with p probability.
The expected value of the binomial distribution is:
In this problem, we have that:
If we were to survey 50 randomly selected adults, find the mean number of adults who would have bank savings accounts.
This is E(X) when .
So
The mean number of adults who would have bank savings accounts is 32.