Instructions: This assignment is worth 30 points. Print out this sheet and write your answers here.

Write the answer with the problem number indicated,and upload the Excel file that backs up your work.

Head injured

Head not injured

totals

Helmet

96

656

No helmet

480

2330

Totals

Answer the following questions, using the Excel sheet as your calculator (4 pts each)

Considering the table above, which contains data from an article "Helmet Use and Risk of Head Injuries in Alpine Skiers and Snowboarders," which appeared in the Journal of the American Medical Association:

1.)Fill in the totals for all columns, rows, and overall in the table above.

2.)If one of the subjects is randomly selected, find the probability of selecting someone with a head injury

3.)If one of the subjects is randomly selected, find the probability of selecting someone who had a head injury or wore a helmet.

4.)If one of the subjects is randomly selected, find the probability of selecting someone who did not wear a helmet or was not injured.

5.)If one of the subjects is randomly selected, find the probability of selecting someone who wore a helmet and was injured.

6.)If one of the subjects is randomly selected, find the probability of selecting someone who did not wear a helmet and was not injured.

7.)If two different subjects are randomly selected, find the probability that they both wore helmets.

8.)If one of the subjects is randomly selected, find the probability of selecting someone who did not havea helmet, given that the subject has head injuries.