The number of unhealthy days based on the AQI (Air Quality Index) for a random sample of metropolitan areas is shown. Construct a 98% confidence interval for the population mean based on the given data.

611264027389351340

Select one:

a.

9.3 < < 57.7

b.

13.1 < < 53.9

c.

8.8 < < 58.2

d.

6.8 < < 55.2