He should use a sample size of 655.
We can use the formula

We find the z-value by first subtracting the confidence level from 1:
1 - 0.8 = 0.2
Divide this by 2:
0.2/2 = 0.1
Subtract this from 1:
1 - 0.1 = 0.9
Using a z-table (http://www.z-table.com) we find the z-score associated with this is 1.28.
Now we plug our information into our formula:
Answer:
a>option B
b>option C
c>option B
d>option C
e>option A
Step-by-step explanation:
the resons are well defined in the options
Answer:
235or 236
Step-by-step explanation:
A cone has a radius of 5 cm
a height of 9 cm
Volume of cone =1/3πr^2h
=1/3×3.14×5×5×9
= 3.14×25×3
=3.14×75
=235.5
=235or 236 is the answer
Answer:
18
Step-by-step explanation:
4(3)=12
12+6=18
Answer: 57
Step-by-step explanation:
6{-4[-5+7-(10)]+7}-9
6{-4[-1]+7}-9
6{11}-9
66-9=57