Plz help me will give brainlyest
1 answer:
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(side note: your formula C = 2πr^2 is incorrect, it should be C = 2πr)
Answer:
r = 9
Step-by-step explanation:
First let's find the circumference of Circle A. To use the formula we need radius. Since we have a diameter just divide by 2 to get radius. 27 / 2 = 13.5
Now plug that into C = 2πr: 2π*(13.5) = 27π
The question says that the area of circle B is 3x this value, so Circle B's area must be: 27π * 3 = 81π
Now plug that into A = πr^2 and solve for r:
(edited to correct a brain fart)
Answer:
And on this case we have a 0.0303% of chance that the sample variance would be higher than 20. So on this case its not reasonable that the sample variance would be higher than 20.
Step-by-step explanation:
Notation and previous concepts
A chi-square test is "used to test if the variance of a population is equal to a specified value. This test can be either a two-sided test or a one-sided test. The two-sided version tests against the alternative that the true variance is either less than or greater than the specified value"
represent the sample size
represent the sample variance obtained
represent the population variance
We can calculate the probability that would be higher than 20 and we will have an idea how to solve the problem.
For this case we can use the following statistic:
And this statistic is distributed chi square with n-1 degrees of freedom. We have eveything to replace.
Calculate the probability
We can calculate the probability that would be higher than 20. The degrees of freedom are given by n-1=20-1=19
And hte reason of this is this one:
In order to calculate this probability we can use the following code in excel:
"==1-CHISQ.DIST(47.5,19,TRUE)"
And on this case we have a 0.0303% of chance that the sample variance would be higher than 20. So on this case its not reasonable that the sample variance would be higher than 20.