Answer:
k
Step-by-step explanation:
Part a is correct.
Part b can be done a couple ways.
1) Use binomial distribution. p = 0.2, n = 144
P(x>3) = 1 - P(x=0) -p(x=1) -p(x=2) -p(x=3)
where

2) Assume a normal distribution with mean = 28.2, stdev = 4.8

Look up z-value in normal table to find probability.
Hope that helps.
Answer:

But we need to calculate the mean with the following formula:

And replacing we got:

And for the sample variance we have:

And thi is the best estimator for the population variance since is an unbiased estimator od the population variance 

Step-by-step explanation:
For this case we have the following data:
1.04,1.00,1.13,1.08,1.11
And in order to estimate the population variance we can use the sample variance formula:

But we need to calculate the mean with the following formula:

And replacing we got:

And for the sample variance we have:

And thi is the best estimator for the population variance since is an unbiased estimator od the population variance 

Answer:
3
Step-by-step explanation:
A direct variation is of the form
y = kx
We know x and y so we can find k
81 = k *27
Divide each side by 27
81/27 = 27k/27
3=k
The constant of variation is 3
Cuboid has 6 faces. If each face was 2m squared, that would be 2m squared times 6 which is 12m squared