The lifetimes of a certain brand of light bulb are normally distributed, with a mean of 3.5 years and a standard deviation of .75 years. What is the probability one of these light bulbs burns out in under two years

0.0228 = 2.28% probability one of these light bulbs burns out in under two years.

Step-by-step explanation:

Normal Probability Distribution:

Problems of normal distributions can be solved using the z-score formula.

In a set with mean and standard deviation , the z-score of a measure X is given by:

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.

Mean of 3.5 years and a standard deviation of .75 years.

This means that

What is the probability one of these light bulbs burns out in under two years?

This is the p-value of Z when X = 2. So

has a p-value of 0.0228

0.0228 = 2.28% probability one of these light bulbs burns out in under two years.

i can try and you the very best that i can.

the central idea is that:

individuals should refuse to cooperate with institutions they believe unjust.

thoreau felt  that governments were more often agents of corruption than justice, even democracies, and that just because the majority feels a certain way does not make it just or correct in absolute terms. he uses the fact that slavery exists in our democracy to support this idea.

he goes on to say that, as a result, people should live true to their own internal laws regarding right and wrong, as a product of reflection and a moral life, rather than following every law that society imposes. 

step-by-step explanation: