Which number(s) below belong to the solution set of the inequality? Check all that apply. 9x >_117 A. 6 B. 8 C. 12 D. 14 E.
1 answer:
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Answer:
The confidence interval of standard deviation is: to
Step-by-step explanation:
Given
See attachment for the formatted data
Solving (a): The mean
This is calculated as:
So, we have:
Solving (b): The standard deviation
This is calculated as:
--- approximated
Solving (c): 95% confidence interval of standard deviation
We have:
So:
Calculate the degree of freedom (df)
Determine the critical value at row and columns
and
So, we have:
---- at
--- at
So, the confidence interval of the standard deviation is:
to
to
to
to
Answer:
Step-by-step explanation:
Given that a researcher is trying to decide how many people to survey.
We have confidence intervals are intervals with middle value as the mean and on either side margin of error.
Confidence interval = Mean ± Margin of error
Thus confidence interval width depends on margin of error.
Margin of error =
Thus for the same confidence level and std deviation we find margin of error is inversely proportional to square root of sample size.
Hence for small n we get wide intervals.
So if sample size = 300, the researcher will get wider confidence interval