Answer:
($47.245; $61.575)
Step-by-step explanation:
Mean sample repair cost (X) = $54.41
Standard deviation (s) = $28.89
Sample size (n) =44
Z-score for a 90% confidence interval (z) = 1.645
The confidence interval, assuming a normal distribution, is given by:
Applying the given data, the lower (L) and upper (U) bounds of the interval are:
The confidence interval is I = ($47.245; $61.575)