I have to find out how many quarters and dimes equal $2.05 with 13 total coins
2 answers:
You might be interested in
Answer:
d) [-16.03,-3.97]
.
Step-by-step explanation:
Notation and 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 of A
represent the sample of B
represent the mean sample for A
represent the mean sample for B
represent the sample deviation for A
represent the sample deviation for B
represent the significance level
Confidence =99% or 0.99
The confidence interval for the difference of means is given by the following formula:
(1)
The point of estimate for is just given by:
The appropiate degrees of freedom are
Since the Confidence is 0.99 or 99%, the value of and
, and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-T.INV(0.005,29)".And we see that
The standard error is given by the following formula:
And replacing we have:
Confidence interval
Now we have everything in order to replace into formula (1):
So on this case the 99% confidence interval for the differences of means would be given by .
d) [-16.03,-3.97]