If the standard deviation is 9 and sample size is 100 then the standard error is 0.9.
Given that the mean is 80,standard deviation be 9 and sample size be 100.
We are required to find the standard error of the given data.
The standard error of a statistic is basically the standard deviation of its sampling distribution or an estimate of that standard deviation.
Standard error=σ/![\sqrt{n}](https://tex.z-dn.net/?f=%5Csqrt%7Bn%7D)
in which σ is standard deviation and n is sample size.
Here standard deviation is 9 and sample size is 100.
Standard deviation=9/![\sqrt{100}](https://tex.z-dn.net/?f=%5Csqrt%7B100%7D)
=9/10
=0.9
Hence if the standard deviation is 9 and sample size is 100 then the standard error is 0.9.
Learn more about standard error at brainly.com/question/1191244
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