---
url: "https://questionstar.com/principles-of-survey-research/chapter-4/slide-153.html"
title: "What the Margin of Error Formula Tells Us"
type: "lehrbuch-slide"
chapter: 4
chapterTitle: "Sampling"
slide: 153
---

# 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.*

![E = z · sqrt(π(1−π)/n)](/principles-of-survey-research/media/formel_verhaeltnisse.png)

n ↑

lowers E

z ↑

raises E

The only lever to **lower** the margin of error is a larger **n** — everything else is fixed.

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.

---

*Slide 153 of 274 · Chapter 4: Sampling · Principles of Survey Research · Dr. Paul Marx*