17. Example 1: Ramu car has average of 15 miles with
petrol on the highway. He switched his car to gas by an
advertisement of increase to gas mileage. After driving
of 3000 km with gas, he wants to determine if the
average of gas mileage has increased.
Example 2: In a national survey of 1028 teenagers
revealed that 72% of teens said that argue or never
argue with their friends . You wonder weather this
national survey in your college. So you conduct your
own survey of random sample of students at your
college.