Question

The manufacturing team of a toothbrush manufacturing company was very sure about their product, that a brush would last 300 days. Testing team randomly selects 15 toothbrushes for testing. The sampled brushes, on testing, did work for 290 days with an SD of 50 days. If the manufacturing team's claim were true, what is the probability that 15 randomly selected brushes would have an average life of no more than 290 days?

Answer 1

Answer:

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