The number of unhealthy days based on the AQ1 Air Quality In

The number of unhealthy days based on the AQ1 (Air Quality Index) for a random sample of metropolitan areas is shown. Construct a 99% confidence interval for the true mean based on the data. The mean salary of federal government employees on the General Schedule is $59,500. The average salary of 30 state employees who do similar work is $58,900 with Ate the 0.02 level of significance, can it be concluded that state employees earn on average less than federal employees?

Solution

11.

Note that              
              
Lower Bound = X - t(alpha/2) * s / sqrt(n)              
Upper Bound = X + t(alpha/2) * s / sqrt(n)              
              
where              
alpha/2 = (1 - confidence level)/2 =    0.005          
X = sample mean =    33.5          
t(alpha/2) = critical t for the confidence interval =    3.249835542          
s = sample standard deviation =    27.67770864          
n = sample size =    10          
df = n - 1 =    9          
Thus,              
              
Lower bound =    5.055944508          
Upper bound =    61.94405549          
              
Thus, the confidence interval is              
              
(   5.055944508   ,   61.94405549   ) [ANSWER]

*******************************************

Hi! Please submit the next part as a separate question. That way we can continue helping you! Please indicate which parts are not yet solved when you submit. Thanks!