Suppose the average age of a passenger train car is 19.1 years. If the distribution of ages is normal and 20% of the cars are older than 21.5 years, find the standard deviation. Round final answer to two decimal places.
I know that first I take .2000-.5000=3000 then I get stuckYou need to read the rules of this forum. Please read the post titled "Read before Posting" at the following URL:
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I know that first I take .2000-.5000= - .3000 then i get stuck