In: Statistics and Probability
A traffic safety company publishes reports about motorcycle fatalities and helmet use. In the first accompanying data table, the distribution shows the proportion of fatalities by location of injury for motorcycle accidents. The second data table shows the location of injury and fatalities for 2051 riders not wearing a helmet. Complete parts (a) and (b) below.
Location of injury Multiple locations Head Neck Thorax Abdomen/ Lumbar/ Spine
Proportion 0.570 0.310 0.030 0.060 0.030
Location of injury Multiple locations Head Neck Thorax Abdomen/ Lumbar/ Spine
Number 1029 857 36 82 47
a) Does the distribution of fatal injuries for riders not wearing a helmet follow the distribution for all riders? Use a = 0.01 level of significance. What are the null and alternativehypotheses?
A. H0: The distribution of fatal injuries for riders not wearing a helmet follows the same distribution for all other riders.
H1: The distribution of fatal injuries for riders not wearing a helmet does not follow the same distribution for all other riders.
B. H0: The distribution of fatal injuries for riders not wearing a helmet does not follow the same distribution for all other riders.
H1: The distribution of fatal injuries for riders not wearing a helmet does follow the same distribution for all other riders.
C. None of these.
Location of Injury Observed Count Expected Count
Multiple Locations 1029 ?
Head 857 ?
Neck 36 ?
Thorax 82 ?
Abdomen/lumbar/ 47 ?
spine
(round to 2 decimal places as needed)
What is the p value of the test?
P value = __ (Round to 3 decimal places as needed)
Based on the results, does the distribution of fatal injuries for riders not wearing a helmet follow the distribution for all other riders at a significance level of a = 0.01?
A. Do not reject Upper H 0. There is sufficient evidence that the distribution of fatal injuries for riders not wearing a helmet follows the distribution for all riders.
B. Reject Upper H 0. There is sufficient evidence that the distribution of fatal injuries for riders not wearing a helmet does not follow the distribution for all riders.
C. Reject Upper H 0. There is not sufficient evidence that the distribution of fatal injuries for riders not wearing a helmet follows the distribution for all riders.
D. Do not reject Upper H 0. There is not sufficient evidence that the distribution of fatal injuries for riders not wearing a helmet does not follow the distribution for all riders
(b) Compare the observed and expected counts for each category. What does this information tell you?
A. Motorcycle fatalities from head injuries occur less frequently for riders not wearing a helmet.
B. Motorcycle fatalities from head injuries occur more frequently for riders not wearing a helmet.
C. Motorcycle fatalities from thorax injuries occur more frequently for riders not wearing a helmet
H0: The distribution of fatal injuries for riders not wearing a helmet follows the same distribution for all other riders.
H1: The distribution of fatal injuries for riders not wearing a helmet does not follow the same distribution for all other riders.
option A
Reject Upper H 0. There is sufficient evidence that the distribution of fatal injuries for riders not wearing a helmet does not follow the distribution for all riders.
OPTION B IS CORRECT
b) By comparing and observational counts
HEAD = 635.8/857 = 0.74
NECK = 36/61.5 =0.585
Motorcycle fatalities from head injuries occur more frequently for riders not wearing a helmet.
OPTION B IS CORRECT