Xr12-23 A courier service advertises that its average delivery time is less than 6 hours for local deliveries. A random sample of times for 12 deliveries to an address across town was recorded. These data are shown here.

Is this sufficient evidence to support the courier’s advertisement, at the 5% level of significance?

3.03 6.33 6.50 5.22 3.56 6.76 7.98 4.82 7.96 4.54 5.09 6.46