The following table gives the life time in days for 100 tubelights. Find the mean life time of tubes by assumed mean method.

Suppose that the lifetimes of old-fashioned TV tubes are normally distributed with a standard deviation of 1.2 years. Suppose also that exactly 40% of the TV tubes die before 4 years. Find the mean lifetime of TV tubes. Carry your intermediate computations to at least four decimal places. Round your answer to at least one decimal place.years

The manufacturer of television tubes knows from past experience that the average life of a tubeis 2000 hrs. with a s.d. of 200 hrs. A sample of 100 tubes has an average life of 1950 hrs. Test atthe 0.01 level of significance to see if this sample came from a normal population of mean 2000hrs

A factory produces a type of light tube, Its lifespan can be expressed this way: X~(u, 200^2). From experience, it's known that the average lifespan u is 1500 hours. Now, after adopting a new technique, 25 light tubes are randomly selected from those produced and the average lifespan is found to be 1675 hours. With the new technique adopted, what is the value of the test statistic?

The lifetime t (in weeks) of a light bulb can be defined by the force of mortality 0.25t2 +0.4t.A hotel has five hundred rooms, and has just opened with four new light bulbs in eachroom. Light bulbs are checked exactly once a week and all defective bulbs are replacedimmediately.(a) Calculate the number of bulbs that the hotel would expect to replace at the end ofeach of the first, second, and third week of opening

You are growing bacteria in the lab and have added a drug that stops the bacteria from growing and kills them at an hourly rate of 0.8 per capita. What is the mean lifetime of a bacterium in this population?Group of answer choices8 hours1.25 hours0.2 hours0.8 hours