math

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Can someone assit me with my two math problems

Assume that the salaries of elementary school teachers in the united states are normally distributed with the mean of 36,000 and a standard deviation of 6,000. What is the cut off salary for teachers in the bottom 10%?



A physical fitness association is including the mile run in its secondary-school fitness test. The time for this event for boys in secondary school is known to possess a normal distribution with a mean of 450 seconds and a standard deviation of 40 seconds. The fitness association wants to recognize the fastest 10% of the boys with certificates of recognition. What time would the boys need to beat in order to earn a certificate of recognition from the fitness association?

  • math -

    Z = (raw score - mean)/standard deviation

    Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion in smallest area = .10. Insert that Z score and your other data in the equation above to get your answer.

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