Answer:
z = 1.476
Step-by-step explanation:
We have that to find our
level, that is the subtraction of 1 by the confidence interval divided by 2. So:

Now, we have to find z in the Ztable as such z has a pvalue of
.
So it is z with a pvalue of
, so 
The answer is z = 1.476
The width of this box is 80
Each person shakes 7 hands, but once you count the handshake between A and B, you don't need to count the handshake between B and A. There are a total of 8*7/2 = 28 handshakes.
(4^2)p=4^14
p=4^14/4^2
p=4^12