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:
27
Step-by-step explanation:
3².2³/2² + 3².2²/2² = 27
I believe the answer is 1.2
Newton discovered that sunlight has many colors when it passes through a prism.
I hope this helped! Mark me Brainliest! :) -Raven❤️