Math Problem Statement
The maintenance department at the main campus of a large state university receives daily requests to replace fluorecent lightbulbs. The distribution of the number of daily requests is bell-shaped and has a mean of 52 and a standard deviation of 10. Using the 68-95-99.7 rule, what is the approximate percentage of lightbulb replacement requests numbering between 52 and 82?
Do not enter the percent symbol. ans = %
Solution
The 68-95-99.7 rule (also known as the empirical rule) tells us that for a normal distribution:
- 68% of the data falls within 1 standard deviation of the mean.
- 95% of the data falls within 2 standard deviations of the mean.
- 99.7% of the data falls within 3 standard deviations of the mean.
Given:
- Mean = 52
- Standard deviation = 10
We are asked to find the percentage of lightbulb replacement requests between 52 and 82.
First, calculate how many standard deviations 82 is from the mean: 82 is 3 standard deviations above the mean.
According to the 68-95-99.7 rule, the percentage of values between the mean and 3 standard deviations above the mean is half of the 99.7% (since we're only considering the right side of the mean):
Therefore, the approximate percentage of requests between 52 and 82 is 49.85%.
Would you like more details or have any questions? Here are 5 related questions for further exploration:
- What percentage of lightbulb replacement requests fall between 42 and 62?
- What percentage of requests are below 42?
- How would the rule apply for requests between 32 and 72?
- How do you calculate percentages for non-standard deviations like 1.5 or 2.5?
- What would be the approximate number of requests above 82?
Tip: When applying the empirical rule, always remember that percentages beyond 3 standard deviations are rare events (approximately 0.3%).
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Math Problem Analysis
Mathematical Concepts
Statistics
Normal Distribution
Empirical Rule (68-95-99.7 Rule)
Formulas
(x - mean) / standard deviation
Empirical Rule percentages
Theorems
Empirical Rule (68-95-99.7 Rule)
Suitable Grade Level
Grades 9-12
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