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:
c
Step-by-step explanation:
I don't trust myself so I am sorry if it is wrong
Answer:
okay?
Step-by-step explanation:
is that supposed to be like is that true or false or am I just not understanding if that's a question or not
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hi my name is antonette Jane S pascua please help me my question thank you for your answer