there is 12 less iphones than androids. if there is a total of 72 iphones and androids, how many iphones are there?
2 answers:
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Answer:
The 90% confidence interval is ($105.55,$111.45)
The 95% confidence interval is ($104.98,$112.02)
The 95% confidence interval is wider.
C. You can be 90% confident that the population mean price of the stock is between the bounds of the 90% confidenceinterval, and 95% confident for the 95% interval.
Step-by-step explanation:
90% confidence interval:
We have that to find our level, that is the subtraction of 1 by the confidence interval divided by 2. So:
Now, we have to find z in the Ztable as such z has a pvalue of .
That is z with a pvalue of , so Z = 1.645.
Now, find the margin of error M as such
In which is the standard deviation of the population and n is the size of the sample.
The lower end of the interval is the sample mean subtracted by M. So it is 108.50 - 2.95 = $105.55
The upper end of the interval is the sample mean added to M. So it is 108.50 + 2.95 = $111.45
The 90% confidence interval is ($105.55,$111.45)
95% confidence interval:
We have that to find our level, that is the subtraction of 1 by the confidence interval divided by 2. So:
Now, we have to find z in the Ztable as such z has a pvalue of .
That is z with a pvalue of , so Z = 1.96.
Now, find the margin of error M as such
In which is the standard deviation of the population and n is the size of the sample.
The lower end of the interval is the sample mean subtracted by M. So it is 108.50 - 3.52 = $104.98
The upper end of the interval is the sample mean added to M. So it is 108.50 + 3.52 = $112.02
The 95% confidence interval is ($104.98,$112.02)
Which interval is wider?
The 95% confidence interval has a larger margin of error, so it is wider.
x% confidence interval:
A confidence interval is built from a sample, has bounds a and b, and has a confidence level of x%. It means that we are x% confident that the population mean is between a and b.
So the correct interpretation is:
C. You can be 90% confident that the population mean price of the stock is between the bounds of the 90% confidenceinterval, and 95% confident for the 95% interval.