Determine whether each conclusion is valid. Justify your answer. To evaluate the quality of their product, a manufacturer of cell phones
checks every 50th phone off the assembly line. Out of 200 phones
tested, 4 are defective. The manager concludes that about 2% of the cell
phones produced will be defective.
2. To determine whether the students will attend an arts festival at the
school, Oliver surveys his friends in the art club. All of Oliver's friends
plan to attend. So, Oliver assumes that all the students at his school will
also attend.
I
Preferred Ways to Travel
3 A random sample of people at a mall shows that 22 prefer to take a
family trip by car, 18 prefer to travel by plane, and 4 prefer to travel by
bus. Is the sample method valid? If so, how many people out of 500
would you expect to say they prefer to travel by plane? (Example 4)
Bus
9%
Plane
41%
Car
50%