If the owner of a gasoline station wants to study gasoline purchasing habits by motorists at his station. A random sample of 30 motorists during a certain week is selected, with the following results:...

If the owner of a gasoline station wants to study gasoline purchasing habits by motorists at his station. A random sample of 30 motorists during a certain week is selected, with the following results:
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Amount purchased ? = 11.3 gallons, s = 3.1 gallons
10 motorists purchased premium grade gasoline
At the 0.10 level of significance, is there evidence that the mean purchase is different from 10 gallons?
At the 0.10 level of significance, is there evidence that fewer than 40% of the motorists purchase premium grade gasoline?