Chapter 4 · Sampling · Slide 153/274
What the Margin of Error Formula Tells Us
The only lever to lower the margin of error is a larger n — everything else is fixed.
4.4 · Sample Size
Takeaway
What the Margin of Error Formula Tells Us
n ↑
lowers E
z ↑
raises E
1
The only lever to lower the margin of error is a larger n — everything else is fixed.
2
More certainty means a larger z → the margin of error grows → you need an even larger n to push it back down.
Smaller margins of error require larger samples.
Higher confidence levels require larger samples.
QUESTIONSTAR · Dr. Paul Marx
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