The answer is 3.3 hope this helps you .Skateboards
Answer:
a) 
With:


b) 

c) 

d) 


Step-by-step explanation:
For this case we know the following propoertis for the random variable X

We select a sample size of n = 81
Part a
Since the sample size is large enough we can use the central limit distribution and the distribution for the sampel mean on this case would be:

With:


Part b
We want this probability:

We can use the z score formula given by:

And if we find the z score for 89 we got:


Part c

We can use the z score formula given by:

And if we find the z score for 75.65 we got:


Part d
We want this probability:

We find the z scores:



Answer:
each side of the patio measures ft.
Well if the student already finished 6 problems out of 15, there are 15-6 = 9 homework questions she still has to finish.
Still needs to complete: 9.
Already finished: 6
9 : 6.
Simplified: 3 : 2