A study is conducted to assess whether a new style of helmet is effective in red
ID: 3045111 • Letter: A
Question
A study is conducted to assess whether a new style of helmet is effective in reducing concussions for football players. 400 players are randomly assigned to the new helmet group and 400 to the usual helmet group. The new and old style helmets were indistinguishable from each other, and the players, coaches and team physicians did not know which style the players had been assigned. They all then play a normal season (let's assume they all had more or less the same amount of playing time, number of practices, etc.)
At the end of the season, the researchers tally the number of concussions that occurred during the season, as diagnosed by team physicians. Wearers of the old helmets experienced 25 concussions, and wearers of the new helmets experienced 40 concussions.
The prevalence of concussion in this study is: ____% (Express as a percentage to the hundredths [two] decimal place)
Using the above helmet data, what is the relative risk of wearing a new style helmet, comparing the proportion who experienced concussions by the end of the season? Use the tenths place for your answer.
Explanation / Answer
Answer:
A study is conducted to assess whether a new style of helmet is effective in reducing concussions for football players. 400 players are randomly assigned to the new helmet group and 400 to the usual helmet group. The new and old style helmets were indistinguishable from each other, and the players, coaches and team physicians did not know which style the players had been assigned. They all then play a normal season (let's assume they all had more or less the same amount of playing time, number of practices, etc.)
At the end of the season, the researchers tally the number of concussions that occurred during the season, as diagnosed by team physicians. Wearers of the old helmets experienced 25 concussions, and wearers of the new helmets experienced 40 concussions.
New
Old
concussion
40
25
65
No concussion
360
375
735
400
400
800
65/800 =0.0813
The prevalence of concussion in this study is: 8.13% (Express as a percentage to the hundredths [two] decimal place)
Using the above helmet data, what is the relative risk of wearing a new style helmet, comparing the proportion who experienced concussions by the end of the season? Use the tenths place for your answer.
Risk in new group = 40/400 =0.10
Risk in old group = 25/400=0.0625
Relative Risk =0.10/0.0625
=1.6
New
Old
concussion
40
25
65
No concussion
360
375
735
400
400
800
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