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

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Question 12 Partially Correct Your answer is incorrect. Expected number of colorblind participants who had an outcome of hit: Your answer is incorrect. Expected number of colorblind participants who had an outcome of false alarm: Your answer is incorrect. The following contingency table gives a summary of the data from 2000 trials of a visual experiment. Each of the trials was classified according to two variables: color vision of the participant ("Colorblind" or "Not colorblind") and trial outcome ("Hit", "Miss", "False alarm", or "Correct rejection"). 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, color vision of participant and trial outcome, are independent. Round your answers to two or more decimal places.

Send data to Excel Trial outcome Hit Miss False alarm Correct rejection Total Color vision of participant Colorblind 77 639.13 22 23 263.36 70 67.97 192 Not colorblind 630 269 271 638 1808 Total 707 291 294 708 2000

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Solution

To find the expected frequencies in the blanks of a contingency table under the assumption that the two variables (color vision and trial outcome) are independent, we’ll use the formula for expected frequency in each cell:

Eij=(Row Total for Row i)×(Column Total for Column j)Grand TotalE_{ij} = \frac{( \text{Row Total for Row i}) \times (\text{Column Total for Column j})}{\text{Grand Total}}

The given table is as follows, with blanks indicated:

Trial OutcomeHitMissFalse AlarmCorrect RejectionTotal
Colorblind77639.132223263.36
Not Colorblind6302692716381808
Total7072912947082000

Step 1: Calculate Missing Expected Frequencies

Using the formula, let’s calculate each expected frequency for the blank cells.

  1. Expected number of Colorblind participants with outcome "Miss"
    E=(Row Total for Colorblind)×(Column Total for Miss)Grand Total=263.36×2912000=38.22E = \frac{(\text{Row Total for Colorblind}) \times (\text{Column Total for Miss})}{\text{Grand Total}} = \frac{263.36 \times 291}{2000} = 38.22

  2. Expected number of Colorblind participants with outcome "Correct Rejection"
    E=(263.36)×(708)2000=93.01E = \frac{(263.36) \times (708)}{2000} = 93.01

  3. Expected number of Colorblind participants with outcome "False Alarm"
    E=(263.36)×(294)2000=38.67E = \frac{(263.36) \times (294)}{2000} = 38.67

Summary of Expected Frequencies in Blank Cells

  • Miss (Colorblind): 38.2238.22
  • Correct Rejection (Colorblind): 93.0193.01
  • False Alarm (Colorblind): 38.6738.67

Let me know if you'd like further clarification on any of these steps or if you have any other questions!


Related Questions

  1. How would you calculate the probability of a hit outcome regardless of color vision?
  2. If these values were actual outcomes, what would be the next step to analyze independence between variables?
  3. What are common reasons to test for independence in contingency tables?
  4. How does sample size affect the expected frequencies in contingency tables?
  5. What are the limitations of using expected frequencies in assessing independence?

Tip

When dealing with large contingency tables, breaking down each calculation step can help reduce mistakes and provide a clear path to the final answer.

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Math Problem Analysis

Mathematical Concepts

Statistics
Probability
Contingency Tables
Expected Frequency Calculation

Formulas

Expected Frequency E_ij = (Row Total for Row i * Column Total for Column j) / Grand Total

Theorems

Independence of Events in Probability

Suitable Grade Level

College Level (Statistics Course)