Standard dev. est. at 100 hrs: sample size for 99.73% conf.

G

Godisgood

New member
Joined
Apr 17, 2009
Messages
13
If the standard deviation of the lifetimes of television tubes is estimated as 100 hours how large a sample must be taken in order to be 99.73% confident that the error in the estimated mean lifetime will not exceed 20 hours?
 
Re: Standard deviation

Godisgood said:
If the standard deviation of the lifetimes of television tubes is estimated as 100 hours how large a sample must be taken in order to be 99.73% confident that the error in the estimated mean lifetime will not exceed 20 hours?
Click to expand...
You have posted 5 problems - without showing a line of work.

Please show us your work, indicating exactly where you are stuck - so that we know where to begin to help you.
 
You must log in or register to reply here.
Top