If the length of a confidence interval is 3 for inference concerning a mean, the required sample size is [tex](z_\frac{\alpha }{2}*\frac{\sigma}{3} )^2[/tex]
An equation is an expression that shows the relationship between two or more variables and numbers.
σ = standard deviation, n = sample size, the margin of error (E) is given by:
[tex]E=z_\frac{\alpha }{2}*\frac{\sigma}{\sqrt{n} } \\\\E=3, hence:\\\\3=z_\frac{\alpha }{2}*\frac{\sigma}{\sqrt{n} } \\\\n=(z_\frac{\alpha }{2}*\frac{\sigma}{3} )^2[/tex]
If the length of a confidence interval is 3 for inference concerning a mean, the required sample size is [tex](z_\frac{\alpha }{2}*\frac{\sigma}{3} )^2[/tex]
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