Sarah, a self employed blogger, has adjusted gross earnings of $45,162 this year. Find the amount of social security and Medicar
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Answer:
a) The 99% confidence interval would be given by (5004.168;12603.832)
b) For this case we can use the lower bound for the confidence interval as estimation, on this case 5004.168. But we need to take in count that this value it's with 99% of confidence and 1% of significance and 1% of probability to commit type Error I
Step-by-step explanation:
1) 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=5629 represent the sample standard deviation
n=20 represent the sample size
2) Part a
The confidence interval for the mean is given by the following formula:
(1)
In order to calculate the critical value we need to find first the degrees of freedom, given by:
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(0.005,19)".And we see that
Now we have everything in order to replace into formula (1):
So on this case the 99% confidence interval would be given by (5004.168;12603.832)
3) Part b
For this case we can use the lower bound for the confidence interval as estimation, on this case 5004.168. But we need to take in count that this value it's with 99% of confidence and 1% of significance and 1% of probability to commit type Error I
The average rate of change of the population from 2007 to 2012 is
which is to say that every five years you can expect 29 more visitors.
So if there were 607 visitors in 2010, then you could expect around 607+2*29=665 visitors in the year 2020.
which is to say that every five years you can expect 29 more visitors.
So if there were 607 visitors in 2010, then you could expect around 607+2*29=665 visitors in the year 2020.