Answer:
The approximate percentage of lightbulb replacement requests numbering between 10 and 43 is of 49.85%.
Step-by-step explanation:
The Empirical Rule states that, for a normally distributed random variable:
Approximately 68% of the measures are within 1 standard deviation of the mean.
Approximately 95% of the measures are within 2 standard deviations of the mean.
Approximately 99.7% of the measures are within 3 standard deviations of the mean.
In this problem, we have that:
Mean = 43
Standard deviation = 11
The normal distribution is symmetric, which means that 50% of the measures are below the mean and 50% are above the mean.
What is the approximate percentage of lightbulb replacement requests numbering between 10 and 43?
43 is the mean
10 = 43 - 3*11
So 10 is 3 standard deviations below the mean.
Of the 50% of measures below the mean, 99.7% are between 3 standard deviations below the mean(10) and the mean(43). So
0.5*0.997 = 0.4985.
0.4985*100% = 49.85%.
The approximate percentage of lightbulb replacement requests numbering between 10 and 43 is of 49.85%.
