Margins of error

<p>A number calculated from a <a href="/category/glossary/random-sample">random sample</a> that estimates the likely size of the <a href="/category/glossary/sampling-error">sampling error</a> in an <a href="/category/glossary/estimate">estimate</a> of a <a href="/category/glossary/population-parameters">population parameter</a>.</p>
<p>The margin of error is added to and subtracted from a <a href="/category/glossary/point-estimate">point estimate</a> of a population parameter to form a <a href="/category/glossary/confidence-interval">confidence interval</a> for a population parameter, usually with a <a href="/category/glossary/confidence-level">confidence level</a> of 95%. The margin of error is therefore half of the width of a confidence interval.</p>
<p>Generally a larger <a href="/category/glossary/sample-size">sample size</a> will give a smaller margin of error.</p>
<p>The higher the confidence level, the greater the margin of error.<br />
<img src="/sites/default/files/images/margin.JPG" /><br />
<strong><br />
Curriculum achievement objectives references</strong><br />
Statistical investigation: Level 8<br />
Statistical literacy: Level 8</p>