The expression c + 0.07c can be used to find the total cost of an item with 7% sales tax, where c is the cost of the item. Use t
1 answer:
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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 = 64
Part a
Since the sample size is large enough we can use the central limit distribution and the distribution for the sample 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 89.7 we got:
Part c
We can use the z score formula given by:
And if we find the z score for 85.7 we got:
Part d
We want this probability:
We find the z scores: