Answer :
Answer:
[tex] \mu -\sigma = 1200-75 = 1125[/tex]
[tex] \mu +\sigma = 1200+75 = 1275[/tex]
It can be concluded that approximately 68% of the bulbs will last between:1125 and 1275 hours
Step-by-step explanation:
For this case we know that the random variable X "iife of a particular brand of light bulb " and we know the following distribution:
[tex] X \sim N(\mu = 1200, \sigma =75)[/tex]
And we can use the empirical rule for this case and we know that 68% of the values are within one deviation from the mean and we can find the limits like this:
[tex] \mu -\sigma = 1200-75 = 1125[/tex]
[tex] \mu +\sigma = 1200+75 = 1275[/tex]
It can be concluded that approximately 68% of the bulbs will last between:1125 and 1275 hours