Answer:
So the answer for this case would be n=67 rounded up
Step-by-step explanation:
Information given
represent the sample mean for the sample
population mean
represent the sample standard deviation
n represent the sample size
Solution to the problem
The margin of error is given by this formula:
(a)
And on this case we have that ME =400 and we are interested in order to find the value of n, if we solve n from equation (a) we got:
(b)
The critical value for 98% of confidence interval now can be founded using the normal distribution. And the critical value would be , replacing into formula (b) we got:
So the answer for this case would be n=67 rounded up