Answer :
Answer:
The 95% confidence interval for the average sleep (in hours) that statistics students in the morning class got the night before is between 5.37 hours and 7.63 hours. This means that we are 95% that the true mean sleep that all statistics students in the morning class got the night before is between 5.37 hours and 7.63 hours.
Step-by-step explanation:
We have that to find our [tex]\alpha[/tex] level, that is the subtraction of 1 by the confidence interval divided by 2. So:
[tex]\alpha = \frac{1-0.95}{2} = 0.025[/tex]
Now, we have to find z in the Ztable as such z has a pvalue of [tex]1-\alpha[/tex].
So it is z with a pvalue of [tex]1-0.025 = 0.975[/tex], so [tex]z = 1.96[/tex]
Now, find M as such
[tex]M = z*\frac{\sigma}{\sqrt{n}}[/tex]
In which [tex]\sigma[/tex] is the standard deviation of the population and n is the size of the sample.
[tex]M = 1.96*\frac{3.2}{\sqrt{31}} = 1.13[/tex]
The lower end of the interval is the mean subtracted by M. So it is 6.5 - 1.13 = 5.37 hours
The upper end of the interval is the mean added to M. So it is 6.5 + 1.13 = 7.63 hours
The 95% confidence interval for the average sleep (in hours) that statistics students in the morning class got the night before is between 5.37 hours and 7.63 hours. This means that we are 95% that the true mean sleep that all statistics students in the morning class got the night before is between 5.37 hours and 7.63 hours.