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:
X is equal to 8. The work for that is on the attached picture.
Whenever you multiply something, you just add it to itself that many times.
ex) 7 × 4 = 7 + 7 + 7 + 7.
Thus n × a = n + n + n + n....a times.
ANSWER:-
<em>Heya</em><em> </em><em>mate</em><em>,</em><em> </em>
<em>The</em><em> </em><em>answer</em><em> </em><em>is</em><em> </em><em>Option</em><em> </em><em>D</em>
24 + 18 + A = 60
I think this is false. You should probably try reading the question first, otherwise you can't try to figure out what the question is asking you to solve in the first place!