Answer:
The 99% confidence interval for the mean number of hours of part-time work per week for all college students is between 25.8 and 30.2.
Step-by-step explanation:
A confidence interval has the following format.
[tex]\mu_{x} \pm M[/tex]
In which [tex]\mu_{x}[/tex] is the mean of the sample and M is the margin of error.
In this problem, we have that:
[tex]\mu_{x} = 28, M = 2.2[/tex]
[tex]\mu_{x} - M = 28 - 2.2 = 25.8[/tex]
[tex]\mu_{x} + M = 28 + 2.2 = 30.2[/tex]
The 99% confidence interval for the mean number of hours of part-time work per week for all college students is between 25.8 and 30.2.