2. • IN ORDER TO CHECK FOR A RELATIONSHIP BETWEEN HEAD INJURIES AND
SOCCER PARTICIPATION, A STUDY ASKED 240 RANDOMLY SELECTED COLLEGE
STUDENTS ABOUT HEAD INJURIES AND THEIR ACTIVITIES. THE RESULTS ARE
LISTED BELOW.
• DO THE DATA SUGGEST THAT THERE IS A RELATIONSHIP BETWEEN THE NUMBER
OF CONCUSSIONS AND ACTIVITIES OF COLLEGE STUDENTS? BE SURE TO WRITE
YOUR WORK, HYPOTHESIS STATEMENTS, ETC.
0
concussions
1
concussion
2
concussions
3 or more
concussions
Soccer
players
45 25 11 10
Non-soccer
players
68 15 8 5
Non-
athletes
45 5 3 0
3. TAKE A FEW MINUTES TO WORK THIS
PROBLEM AND THEN CHECK YOURSELF ON
THE REMAINING SLIDES!
4. STATE HYPOTHESES:
• HO: THERE IS NO ASSOCIATION BETWEEN NUMBER OF CONCUSSIONS AND
ACTIVITIES OF COLLEGE STUDENTS.
• HA:THERE IS AN ASSOCIATION BETWEEN NUMBER OF CONCUSSIONS AND
ACTIVITIES OF COLLEGE STUDENTS.
5. CHECK CONDITIONS:
• RANDOM – PROBLEM STATED THAT THEY TOOK A RANDOM SAMPLE OF 240
COLLEGE STUDENTS
• LARGE SAMPLE SIZE – NEED TO CHECK EXPECTED COUNTS TO BE SURE THAT
THEY ARE ALL AT LEAST 5. EXPECTED COUNTS ARE BELOW:
• ALL EXPECTED COUNTS ARE NOT AT LEAST 5 – IT DOES NOT MEET THIS
CONDITION – PROCEED WITH CAUTION (AND BE ABLE TO DISCUSS PITFALLS
WITH THE PROBLEM LATER)
0
concussions
1
concussion
2
concussions
3 or more
concussions
Soccer
players
59.515 17.278 8.4473 5.7595
Non-soccer
players
60.823 17.658 8.6329 5.8861
Non-
athletes
34.662 10.063 4.9198 3.3544
7. CONCLUSION:
• SINCE THE P-VALUE IS SO SMALL, WE DO HAVE STATISTICALLY SIGNIFICANT
EVIDENCE TO REJECT THE NULL HYPOTHESIS.
• THERE IS AN ASSOCIATION BETWEEN NUMBER OF CONCUSSIONS AND ACTIVITIES
OF COLLEGE STUDENTS