In order to find the number times something is larger than something, you have to use division where you divide the larger number by the smaller number.
So:
I'm not sure how much you want to round to, but the answer is 387.6063183 times.
You can make sure by multiplying the smaller number by 387.6063183 and you should get the larger number:
Answer:
So the answer for this case would be n=5 rounded up to the nearest integer
Step-by-step explanation:
Previous concepts
A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".
The margin of error is the range of values below and above the sample statistic in a confidence interval.
Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".
represent the sample mean
population mean (variable of interest)
s=2.5 represent the sample standard deviation
n represent the sample size
ME = 2 represent the margin of error accepted
Solution to the problem
The confidence interval for the mean is given by the following formula:
(1)
The margin of error is given by this formula:
(2)
And on this case we have that ME =2 and we are interested in order to find the value of n, if we solve n from equation (2) we got:
(3)
We can use as estimator for the population deviation the sample deviation
The critical value for 90% of confidence interval now can be founded using the normal distribution. And in excel we can use this formla to find it:"=-NORM.INV(0.05;0;1)", and we got , replacing into formula (3) we got:
So the answer for this case would be n=5 rounded up to the nearest integer