The z score for a confidence level of 99% is 2.575.. You need to know this to complete this type of problem.. the other two commonly used confidence levels are 90% and 95% having z scores of 1.645 and 1.96 respectively. You need to memorize this!
To find the confidence interval, it will be defined as the sample mean plus/minus the margin of error.. Now to find the margin of error, divide the standard deviation of 12 by the square root of the number of elements in your sample(√250). Then take that result and multiply it by the Z score I mentioned above for a 99% confidence level.
In this case: the sample mean is 70 and the margin of error is approximately 1.95
So to calculate the confidence interval, do the following:
70 - 1.95 = 68.05 rounded to the nearest whole number is 68
70 + 1.95 = 71.95 rounded to the nearest whole number is 72
Looks like that would be the last choice. hope this helps.. it's been awhile since my work with statistics :-)
Answer:
C. 
Step-by-step explanation:
Let be 
the excedent on annual sales and 
the bonus factor, to determine the bonus amount a composition of 
is 
must be done. That is:
Hence, the right answer is C.
Volume = W*L*H
30 = 5*L*H old one
Volume = 2*5*L*H new one
Volume new one = 2*5*L*H =2*(5*L*H)=2*30=60
Answer is C
<span>23863.05 is the answer to the problem</span>
Answer:
x = 100°
Explanation:
The polygon has 6 sides, meaning it's a hexagon. In the picture you can see the following steps under #1:
(6-2) x 180° = 4 x 180 = 720°
720 is the total amount that all the angles should add up to, including the missing number x.
To solve for x add all of the angles up:
120 + 156 + 145 + (x + 9) + x + 90 = 720
520 + 2x = 720 (subtract 520 from both sides)
-520
2x = 200 (divide 200 by 2 to have x on its own)
x = 100°
To make sure it's correct, plug in the value (100°) for x in the original equation to check the answer:
120 + 156 + 145 + 100 + 9 + 100 + 90 = 720
720 = 720 Correct
