Which Inference Procedure?

How many fewer crimes will happen in an area where police patrol? 50 spots were studied before and after police patrol

Will candidate A win the election? 1500 randomly selected voters were given an exit poll.

What is the difference in the crime rates for African Americans vs. Caucasians? 4000 of each group were observed

How much faster are male swimmers than female swimmers? 40 men and 30 women were selected at random to swim 100 meters

Does taking an SAT prep class improve your SAT score?50 students took the SAT, took a prep class then took the SAT again

10 years ago, the age of CEOs averaged 62 years. Has this number changed? The ages of 80 current CEOs were obtained.

Is a man who walks into a car dealership more likely to purchase an automobile than a woman? 70 men and 60 women sampled

You own a restaurant and want to know how much lettuce is consumed per day. You look at total orders on 45 days

What percent of new calculators are defective? A study was done on 4000 calculators.

Do math students who have a tutor earn a higher grade than those who don't have a tutor? 43 and 72 students sampled