Answer:
Option B
Step-by-step explanation:
Given that two variables in table as
Total Average
x 2 6 7 8 12 35 7
y 15 13 9 8 5 50 10
xy 30 78 63 64 60 295 59
(x-7)^2 25 1 0 1 25 52 10.4
(y-10)^2 25 9 1 4 25 64 12.8
Var x = 10.4 and std dev x = 3.225
Var Y = 12.8 and std dev Y = 3.578
Cov (xy) = E(xy)-E(x) E(Y)=59-70=-11
Correlation coefficient r
= Cov /sx sy = -11/(3.225)(3.578)=-0.9532
Round off to get
r=-0.953
Henceoption B is right.
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:
