Answer:
CI=[ 7.1302,7.2698]
we are 95% confident that the true mean sleeping time lies between the interval[ 7.1302,7.2698]
Step-by-step explanation:
-Given that the sample size, n=1546 the mean is 7.2 hrs and the standard deviation, [tex]\sigma=1.4[/tex]
-The 95% confidence interval can be calculated using the formula:
[tex]CI=\mu\pm z_{\alpha/2}\frac{\sigma}{\sqrt{n}}\\\\=\mu\pm z_{0.025}\times \frac{\sigma}{\sqrt{n}}\\\\=7.2\pm1.96\times \frac{1.4}{\sqrt{1546}}\\\\=7.2\pm 0.0698\\\\CI=[7.1302, \ 7.2698][/tex]
The confidence intervals is therefore 7.1302,7.2698]
Hence, we are 95% confident that the true mean sleeping time lies between the interval[ 7.1302,7.2698]
