A lightbulb has a normally distributed light output with mean 5000 end foot-candles and standard deviation of 50 end foot-candles. Find a lower tolerance limit such that only 0.2% of the bulbs will not exceed this limit. ( I know this is 4856 but I need help with the following)
What fraction of these lightbulbs will have a lower than an output of 5080 end foot-candles ?
If 50000 lightbulbs are made, how many of them will have an output stronger than 5080 end foot-candles?
If 50000 lightbulbs are made, how many of them will have an output weaker than 4890 end foot-candles?