Batches of chemical are manufactured by a production process. Samples of 20 batches from a production run are selected for testing. If the standard deviation of the percentage of impurity contents in the sample batches exceeds 2.5%, the production process is thoroughly checked. Assume that the population distribution of percentage impurity concentrations is normal. What is the probability that the production process will be thoroughly checked if the population standard deviation of percentage impurity concentrations is 2%?
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