We cannot calculate the confidence interval without the sample size. However, for the second question, the sample size needed would be 49.
The formula we use is

To find the z-score:
Convert 98% to a decimal: 0.98
Subtract from 1: 1-0.98 = 0.02
Divide by 2: 0.02/2 = 0.01
Subtract from 1: 1-0.01 = 0.99
Using a z-table (http://www.z-table.com) we see that this value is closest to a z-score of 2.33.
Using the z-score, our standard deviation (9) and our margin of error (3), we have:
<span>2x squared - 5
= 2(x)^2 - 5
= 2(4)^2 - 5
= 2(16) - 5
= 32 - 5
= 27</span>
Answer:
b=(2a-1)/(3a-1)
Step-by-step explanation:
a=(b-1)/(3b-2)
3ab-2a=b-1
3ab-b=2a-1
b(3a-1)=2a-1
b=(2a-1)/(3a-1)
Answer:
Step-by-step explanation:
If you are always included to lead, that leaves 10 students to choose from.
If all that is important is being selected, then there are 10C3 = 120 ways to choose them.
If each selection has a unique duty, then there are 10P3 = 720 ways to assign them their jobs.