Confused with this

Question

3. In a rural area, only 30% of the wells that are drilled find adequate water within a depth of 100 feet or less. A local man Jed Clampett asserts he can do better by “dowsing” - using a forked stick to indicate where the well should be drilled. A sample of 80 of his customers reported that 27 that found water before a depth of 100 feet. Does the data support his claim? Use a α =.10 significance level.

Answer 1

Out of 80 of Jed's customers, 27 found water within 100 ft

 

27 = x%(80)

27 = 80x/100

 

x = 2700/80 = 33.75%

 

Jed's results are better so yes the data supports his claim.