Round 3, 942,588 to the nearest thousand
1 answer:
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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
Answer:
I drew more points as uploaded picture.
We have, arc BD + 210 + 90 = 360 deg
(sum of all arcs on circle)
=> arc BD = 360 - 210 - 90 = 60 deg
Here we have angle CBD = (1/2) x arc CD = (1/2) x 90 = 45 deg
(property of angle on circle)
=> angle ABD = angle ABC - angle CBD = 180 - CBD = 180 - 45 = 135 deg
( A, B, C lie on same line => ABC = 180 deg)
Otherwise, we have:
angle BDA = (1/2) x arc BD = (1/2) x 60 = 30 deg
We have: x + angle BDA + angle ABD = 180 deg
(sum of all angles in a triangle)
=> x = 180 - angle BDA - angle ABD
=> x = 180 -135 - 30
=> x = 15 deg
Hope this helps!
:)
