Answer:
atleast 385
Step-by-step explanation:
Given that an electrical power company is looking to expand into a new market. Before they commit to supplying the new area with electricity, they would like know the mean daily power usage for homes there.
Population std deviation =
Sample size =
STd error of sample mean =
Margin of error for 95% would be Critical value ( std error)
Here since population std dev is known we can use Z critical value= 1.96
Sample size should be atleast 385
Answer:
9 people went swimming and fishing.
Step-by-step explanation:
We solve this question building a Venn Diagram.
We have that:
In total, there are 24 people.
6 do neither of these activities.
x go both swimming and fishing.
15 go swimming. This included those who go both swimming and fishing, so for the addition, we consider those who only go swimming, which is given by 15 - x.
12 go fishing, of which 12 - x only go fishing, by the same logic as above.
How many go swimming and fishing?
This in x
Adding all(neither, both swimming and fishing, only swimming, only fishing), we get 24. So
9 people went swimming and fishing.