Answer:
Mean is 3.05
Standard deviation is 1.69.
Step-by-step explanation:
For each student, there are only two possible outcomes. Either they are foreign, or they are not. This means that we can solve this problem using concepts of the binomial probability distribution.
Binomial probability distribution
The probability of x sucesses on n repeated trials, with p probability.
In this problem, we have a sample of 50 students, so 
. The proportion of all UNC students that are foreign students is 0.061, so 
.
The mean is given by the following formula:
The standard deviation is given by the following formula:
Answer:
23.6 (approximate value)
Step-by-step explanation:
- a*a+b*b=c*c Pythagorean thereom
- (21.5)^2 + b*b = (31.9)^2
- b*b= 1017.61 - 462.25
- √b*b= √555.36
- b=23.6(approximate value)
One centimenter is 0.01 meters. So, you can write the measures as
Once this rewriting is done, getting the total length 
is quite trivial, since all measurements are in the same unit, and we can simply sum everything:
The cube root values and a graph of them are shown in the attachment.
_____
The cube root of a negative number is negative. These all have exact (rational) cube roots.
