While considering three managers for a possible promotion, the company president decided to solicit information from employees about the managers' relative effectiveness. Each person in a random sample of 10 employees who had worked with all three managers was asked to rank the managers, where best is denoted by 1, second best by 2, and worst by 3. The data follow. Based on the survey, are all three managers perceived as equally effective? Explain.

. a1 1 2 1 1 2 1 1 2 2 2 2 1 2 3 1 2 2 1 1 3 3 3 3 2 3 3 3 3 3 n1234567890