The life of a manufacturer's compact fluorescent light bulbs is normal, with mean 12,000 hours and standard deviation 2,000 hours. seth wants to find the probability that a light bulb he purchased from this manufacturer will last no more than 14,500 hours. how many standard deviations above the mean is 14,500 hours?
We have to find how many standard deviations is 14,500 away from the mean. This can be achieved by calculating the z-score
Z-score tells us how many standard deviations above or below is a sample value from the mean. A positive z value shows, sample value is above the mean.
z score can be calculated as = (Sample Value - Mean )/Standard Deviation) So, Z-score =
This means, 14,500 is 1.25 standard deviations above the mean value 12,000.
Explanation:
Mean = 12000;
Standard Deviation = 2000.
We have to find how many standard deviations is 14,500 away from the mean.
This can be achieved by calculating the z-score:
Z-score tells us how many standard deviations above or below is a sample value from the mean. A positive z value shows, sample value is above the mean.
z score can be calculated as = (Sample Value - Mean )/Standard Deviation).
So, Z-score =14500-12000/2000=1.25
Answer: This means, 14,500 is 1.25 standard deviations above the mean value 12,000.
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