Answer:
The 99% confidence interval for the fraction of U.S. adult Twitter users who get some news on Twitter is between 49.34% and 60.66%, which means that we are 99% sure that the true percentage of US adult Twitter users who get some news is in this interval.
Step-by-step explanation:
Confidence interval:
A confidence interval has the following format:
In which M is the sample mean, z is related to the confidence level and s is the standard error.
55% of U.S. adult Twitter users get at least some news on Twitter (Pew, 2013). The standard error for this estimate was 2.2%.
This means that
99% confidence level
So , z is the value of Z that has a pvalue of , so .
Lower bound of the interval:
Upper bound:
The 99% confidence interval for the fraction of U.S. adult Twitter users who get some news on Twitter is between 49.34% and 60.66%, which means that we are 99% sure that the true percentage of US adult Twitter users who get some news is in this interval.
Given:
The diameter of a circle = 20 feet
To find:
The exact circumference of the circle.
Solution:
We know that the radius is half of the diameter of the circle.
The diameter of a circle is 20 feet. So, the radius of the circle is 10 feet.
The circumference of the circle is:
Where, r is the radius.
Substituting , we get
Therefore, the exact circumference of the circle is 62.8 feet.
Note: All options are incorrect.
Answer:
One less than 25, 24, times five is 120, and that is 4 times as much as 30 so you already know it is wrong.
Step-by-step explanation:
C, because every other line is curved and they would not be considered a linear function