Question

Researchers in New Zealand interviewed 907 drivers at age 21. They had data on traffic accidents and they asked their subjects about marijuana use. Here are data on the numbers of accidents caused by these drivers at age 19, broken down by marijuana use at the same age:
Marijuana Use per year
1-10 11-50 51+
Never times times times
Drivers 452 229 70 156
Accidents caused 59 36 15 50

Required:
a. Explain carefully why a useful graph must compare rates (accidents per driver) rather than counts of accidents in the four marijuana use classes.
b. Compute the accident rates in the four marijuana use classes. After you have done this, make a graph that displays the accident rate for each class. What do you conclude? (You can’t conclude that marijuana use causes accidents, because risk takers are more likely both to drive aggressively and to use marijuana.)

Answer 1

Answer:

a)

Therefore to compare this data effectively using the rates per driver is better off like for people who do not smoke their rate will be = 59 / 452 = 13.1% while for smokers of 61+ times = 50 / 156 = 32.1% and this rate will show clearly tat more accidents where caused by people who smoked 51+ times hence it should be used for graphical representation

b) attached below

Step-by-step explanation:

A) A  useful graph is must compare rates rather than counts of accidents in the four marijuana use classes

Using the rates on a graph is better for reference like saying; that 50 crashes were caused by those who smoke 51+ times and 59 crashes is caused by those who never smoke this statistics makes it seem like smoking has no effect on the amount of accidents

Therefore to compare this data effectively using the rates per driver is better off like for people who do not smoke their rate will be = 59 / 452 = 13.1% while for smokers of 61+ times = 50 / 156 = 32.1% and this rate will show clearly tat more accidents where caused by people who smoked 51+ times hence it should be used for graphical representation

B) accident rate for Non-smokers

 = (59/452) * 100 = 13.05

accident rate for smokers between 1-10 times

= ( 36/ 229 ) * 100 = 15.72

accidents rate for smokers between 11 - 50 times

=  ( 15/50 ) * 100 = 21.42

accidents rate for smokers 51+

 =  ( 50 / 156 ) * 100 = 32.05

attached below is the required graph