What is the final cost of an item that is regularly $130.00 but we have reduced by 10%?
2 answers:
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Answer:
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 for the sample
population mean (variable of interest)
s represent the sample standard deviation
n=5 represent the sample size
Solution to the problem
The confidence interval for the mean is given by the following formula:
(1)
And for this case we know that the 95% confidence interval is given by:
And the margin of error is given by:
And the margin of error is given by:
The degrees of freedom are given by:
And the critical value for 95% of confidence is
So then we can find the deviation like this:
And for the 99% confidence the critical value is:
And the margin of error would be:
And the interval is given by: