a) The waiting times for all customers at a supermarket produce a normal distribution with a mean of 5.5 minutes and a standard deviation of 1.5 minutes. Find the probability that the waiting time for a randomly selected customer at this supermarket will be more than 3.25 minutes.
b) In order to qualify for a police academy, candidates must score in the top 10% on a general abilities test. The test has a mean of 200 and a standard deviation of 20. Find the lowest score to qualify. Assume the test scores are normally distributed.
a sstated earlier, this is for references.
b) In order to qualify for a police academy, candidates must score in the top 10% on a general abilities test. The test has a mean of 200 and a standard deviation of 20. Find the lowest score to qualify. Assume the test scores are normally distributed.
a sstated earlier, this is for references.
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qa
z-score = (3.25-5.5)/1.5 = -1.5
P(z>-1.5) = 0.0668 <------
qb
z-score for top 10% = 1.28
score needed = 200 + 1.28*20 = 225.6 ----> 226
z-score = (3.25-5.5)/1.5 = -1.5
P(z>-1.5) = 0.0668 <------
qb
z-score for top 10% = 1.28
score needed = 200 + 1.28*20 = 225.6 ----> 226