Math Problem Statement

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Topic 7 Homework (Nonadaptive) Question 12 of 16 (1 point)|Question Attempt: 5 of Unlimited

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Question 12 In an experimental study, researchers had each of their participants bet on each game of a professional football season. In the contingency table below is some information from a random sample of 100 bets from this study placed on the Columbus Crush (picking them to win) during the last 14 games of the season (the Crush had 7 wins and 7 losses over that period). The table indicates, for each bet placed on the Crush, whether or not the team won and how the participant who placed the bet wagered the following week. Each bet is classified according to two variables: result of picking the Crush ("Crush won" or "Crush lost") and bet placed the following week ("Picked Crush to win" or "Picked Crush to lose"). In the cells of the table are the respective observed frequencies, and three of the cells also have blanks. Fill in these blanks with the frequencies expected if the two variables, result of picking the Crush and bet placed the following week, are independent.

Round your answers to two or more decimal places.

Send data to Excel Bet placed the following week Picked Crush to win Picked Crush to lose Total Result of picking the Crush Crush won 36

19

55 Crush lost 37

8 45 Total 73 27 100

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Solution

To determine the expected frequencies, we need to check if the two variables ("result of picking the Crush" and "bet placed the following week") are independent. We can use the formula for calculating expected frequency in a contingency table:

Expected Frequency=(Row Total)×(Column Total)Grand Total\text{Expected Frequency} = \frac{(\text{Row Total}) \times (\text{Column Total})}{\text{Grand Total}}

Let's calculate each missing value one by one:

Given Data

Bet Placed the Following WeekPicked Crush to WinPicked Crush to LoseTotal
Result of Picking the Crush
Crush Won361955
Crush Lost37845
Total7327100

Missing Values Calculations

  1. Cell for Crush Won / Picked Crush to Lose:

    Using the row total for "Crush Won" (55) and the column total for "Picked Crush to Lose" (27): 55×27100=14.85\frac{55 \times 27}{100} = 14.85

  2. Cell for Crush Lost / Picked Crush to Win:

    Using the row total for "Crush Lost" (45) and the column total for "Picked Crush to Win" (73): 45×73100=32.85\frac{45 \times 73}{100} = 32.85

  3. Cell for Crush Lost / Picked Crush to Lose:

    Using the row total for "Crush Lost" (45) and the column total for "Picked Crush to Lose" (27): 45×27100=12.15\frac{45 \times 27}{100} = 12.15

Filled Table with Expected Frequencies

Bet Placed the Following WeekPicked Crush to WinPicked Crush to LoseTotal
Result of Picking the Crush
Crush Won3614.8555
Crush Lost32.8512.1545
Total7327100

Let me know if you’d like further clarification or have any questions!


Here are five questions to deepen your understanding:

  1. What is the meaning of “independence” in the context of a contingency table?
  2. Why do we use expected frequencies to test for independence?
  3. How would a Chi-square test confirm whether the variables are independent?
  4. What would happen to expected values if the total number of bets increased?
  5. How would these results be interpreted in a practical context, like betting behavior?

Tip: Expected frequencies are essential in hypothesis testing, especially when comparing observed data with a hypothesized distribution.

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Math Problem Analysis

Mathematical Concepts

Statistics
Contingency Tables
Independence Testing

Formulas

Expected Frequency = (Row Total * Column Total) / Grand Total

Theorems

Chi-square Test for Independence

Suitable Grade Level

College Level