Mathematics: Asample of size 36 from a normally distributed population variable with population standard deviation 20 had a sample mean of 88. find a 90% confidence interval for the population mean.

Asample of size 36 from a normally distributed population

pr4ever

13.03.2022

Given the sample mean is $\mu=88$ and population standard deviation is $\sigma=20$ .

Now the standard deviation of the sample mean is $\sigma_X=\frac{\sigma}{\sqrt{n}} =\frac{20}{\sqrt{36}}=3.3333$

The $(1-\alpha )100\%$ confidence interval for population mean is

$\mu_X \pm z_{\alpha /2}\sigma_X$ .

Here $\alpha =0.1,z_{\alpha /2}=-1.645$

The 90% CI for population mean is

$88 \pm 1.645 (3.3333)\\ (82.517,93.483)$

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sadiesnider9

19.09.2021

Deanna’s mean quiz score is approximately is 90.93 Amy’s mean quiz score is approximately is 90.27

Step-by-step explanation:

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