<p>The life, in hours, of a randomly chosen light bulb produced by a manufacturer is normally distributed with mean $1100$ and standard deviation $70$. How large a sample is required such that the probability that the mean life in the sample shall exceed $1120$ is not more than $5\%$? 
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<p>Do you need to use Central Limit Theorem in your working? 
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The life, in hours, of a randomly chosen light bulb produced by a manufacturer is normally distributed with mean $1100$ and standard deviation $70$. How large a sample is required such that the probability that the mean life in the sample shall exceed $1120$ is not more than $5\%$? 


Do you need to use Central Limit Theorem in your working? 


Sampling

International Baccalaureate Higher Level Mathematics

Sampling

Question 7de03495