Solve by factoring x^2-8x-20-0
2 answers:
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Answer:
The probability is 0.003
Step-by-step explanation:
We know that the average is:
The standard deviation is:
The Z-score is:
We seek to find
For P(x>800) The Z-score is:
The score of Z = 3 means that 800 is 3 standard deviations from the mean. Then by the rule of the 8 parts of the normal curve, the area that satisfies the conficion of 3 deviations from the mean has percentage of 0.15%
So
For P(x<200) The Z-score is:
The score of Z = -3 means that 200 is 3 standard deviations from the mean. Then by the rule of the 8 parts of the normal curve, the area that satisfies the conficion of 3 deviations from the mean has percentage of 0.15%
So
Therefore