Let the result of a random experiment be classified as one of the mutually exclusive and exhaustive ways and also as one of the mutually exhaustive ways . Say that 180 independent trials of the experiment result in the following frequencies:
where k is one of the integers 0, 1, 2, 3, 4, 5. What is the smallest value of k that leads to the rejection of the independence of the A attribute and the B attribute at the α = 0.05 significance level?