SOLUTION: Scores for a certian professional exam are approximately normally distributed with a mean of 650 and a standard deviation of 100. 1. What is the probability that a randomly select

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Question 665592: Scores for a certian professional exam are approximately normally distributed with a mean of 650 and a standard deviation of 100.
1. What is the probability that a randomly selected test score is between 450 and 850?
2. Out of 1000 randomly selected test scores, how many would you expect to be between 550 and 950?
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
 

Hi,



You didn't say how You determine the P-value of the z-value found

μ =650   σ = 100

P(  450) - P(z+=+%28450-650%29%2F100)

Out of 1000 randomly selected test scores, how many would you expect to be 

P(550 < x < 950) = P(z+=+%28950-650%29%2F%28100%2Fsqrt%281000%29%29) -  P(z+=+%28550-650%29%2F%28100%2Fsqrt%281000%29%29)

Re TY:  In the case of 'multiplying' each data item by 5: 

mean is 5 times greater as well as is the standard deviation 5 times greater .