Question: A survey of air quality in a city measured X, the amount of suspended particulate matter (in µgm./m³) for fourteen days. The data are:

X: 68 36 22 38 36 39 32 40 42 36 24 34 28 33 38 32

Assume daily amount of particulate matter is normally distributed, obtain the

(a) 98% (b) 95% (c) 90%

confidence interval for mean daily amount of particulate matter in the city.