Question

Mastex 5. A m anufacturer claims that lifespans for their copy machines (in months) can be described by a Normal model N(42,7) (that is, the mean is 42 months and the standard deviation is 7 a. Draw and clearly label the model. A company with several large office buildings buys 200 of these copiers. The salesman tells the boss "190 (95%) of your new copiers will last between months (use 68-95-99.7% rule). What is the third quartile of copier lifespans? b. -_and c. The manufacturer wants to reduce the 36 month failure rate to only 10%. Assuming the mean lifespan will stay the same, what standard deviation must they achieve? d.

Answer 1