Paul started work at compay b ten years ago at the salary shown in the table .at the same time .sharla started at compay c at th
e salary shown in the table .Who earned more during last year ??how much more ???
1 answer:
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Answer:
a)
b)
c) For this case when we increase the sample size the margin of error would be lower and then the interval would be narrower
d) (a)
Solving for n we got:
(b)
And replacing the info we have:
Step-by-step explanation:
Part a
For this case we have the following data given
represent the sample mean for the customer order totals
represent the population deviation
represent the sample size selected
The confidence level is 90% or 0.90 and the significance level would be and
and the critical value from the normal standard distirbution would be given by:
And the confidence interval is given by:
And replacing we got:
Part b
The sample size is now n = 75, but the same confidence so the new interval would be:
Part c
For this case when we increase the sample size the margin of error would be lower and then the interval would be narrower
Part d
The margin of error is given by:
(a)
Solving for n we got:
(b)
And replacing the info we have: