SOLUTION: The time to microwave a bag of popcorn using the automatic setting can be treated as a random variable having a normal distribution standard deviation 10 secohds. If the probabilit
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Question 1180058: The time to microwave a bag of popcorn using the automatic setting can be treated as a random variable having a normal distribution standard deviation 10 secohds. If the probability is 0.8212 that the bag will take less than 282.5 seconds to pop, find the probability that it will take longer than 258.3 seconds to pop. Answer by Boreal(15235) (Show Source):
You can put this solution on YOUR website! 0.8212 is a z of +0.92 from invnorm (0.8212,0,1)ENTER or the table
0.92<(x-mean)/sd
so 9.2
so mean is 273.3 sec
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z>(258.3-273.3)/10 or >-1.5
that probability is 0.9332
mean is 273.3
mean -1 sd is 263.3
mean-2 sd is 253.3
Mean +1 sd is 283.3
