This question refers to X2 test of Association in Statistics My Notes Ask Your I

Question

This question refers to X2 test of Association in Statistics My Notes Ask Your In order to assess the risk of impaired neurocognitive performance due to repeated concussive events, investigators interviewed 89 randomly selected soccer athletes, 100 randomly selected non-soccer athletes, and 51 randomly selected non-athletes. This last group served as the control group. The main interest for the investigative team was whether there was compelling evidence for the existence of chronic neuropsychological dysfunction in the population of collegiate soccer players. Of interest here is whether or not the rates for concussive events are distributed evenly for soccer athletes, non-soccer athletes, and the controls. Table 1 provides cross-tabulated results for this study. Let = 0.1 Note: You do not need to fill in the empty cells of the table, but you may use it for practice if you wish. Table 1: Cross-tab resuits for number of Number ef 2428X-2.564X-9 1100 -0.129-0005302 51 A) Suppose that the researchers now want to find a 90% confidence interval for the true difference in proportion suffering from 3 or more concussions for soccer athletes vs. non- soccer athletes. Find each of the following Note: Calculate as soccer non-soccer a) The margin of error: [0050 b) The 90% confidence interval:-o. b) The 90% confidence interval:-0.009 111 x to i010"- x to Cia B) Suppose that the investigators now want to perform a hypothesis test (still at the = 0.1 level) to see if the proportion of non-athletes that do not experience any concussions is greater than the proportion of soccer players. Note: The comparison here is different than the comparison in part A. a) The proper null/alternative pair for this setting is Ho: ,"soccer-Anon-athlete 0; Ha: Tsoccer . non-athlete > 0 Ho: tsoccer . Anon-athlete 0; Ha: Asoccer . hnon-athlete

Explanation / Answer

a)

Option (4) is Correct

b)

Test Statistic, X^2: 19.6705
Since

c)

Critical X^2:        12.59157
P-Value:             0.0032

d) Here P value 0.0032 < alpha (0.05), we reject H0.

Thus, the proportion of non-athletes than soccer players do not experience concussions

Corres Answer: Option (b)

Oi Ei (Oi-Ei)^2 /Ei 50 62.3 2.428 21 14.83333 2.564 10 7.416667 0.9 8 4.45 2.832 73 70 0.129 17 16.66667 0.007 6 8.333333 0.653 4 5 0.2 45 35.7 2.423 2 8.5 4.971 4 4.25 0.015 0 2.55 2.55 Total: 19.672

Related Questions

Navigate

• Browse (All)
• Browse T
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.