PS296 Chapter Notes - Chapter 7: Level Of Measurement, Abscissa And Ordinate, Odds Ratio
Example:
Study of 100 people with or without children and if they wear seatbelts
With children: 15 wear, 5 do not (20 total have children)
No children: 15 wear, 65 do not (80 do not have children)
-simple probability that a person sampled at random will use a seat belt is 30/100 = .30
-joint probability that a person will have children and will wear a seat belt is 15/100 = .15
-the conditional probability of a person using a set belt given they have children is 15/20 = .
75
-can't calculate joint probability by multiplying appropriate simple probabilities bc use of
multiplicative law requires independent variables and being a parent using seatbelts are not
independent
Writing Up results:
-need to say what the problem is
-how we approached the problem
-where and how we collected the data
-mention important unconditional probabilities
-ex overall probability a person could be sentenced to death and then probabilities for each
race
Document Summary
Study of 100 people with or without children and if they wear seatbelts. With children: 15 wear, 5 do not (20 total have children) No children: 15 wear, 65 do not (80 do not have children) Simple probability that a person sampled at random will use a seat belt is 30/100 = . 30. Joint probability that a person will have children and will wear a seat belt is 15/100 = . 15. The conditional probability of a person using a set belt given they have children is 15/20 = . Can"t calculate joint probability by multiplying appropriate simple probabilities bc use of multiplicative law requires independent variables and being a parent using seatbelts are not independent. Ex overall probability a person could be sentenced to death and then probabilities for each race. Draw conclusions and put study in a context of other work that has been done on topic.
