Question

The XYZ company manufactures a new kind of light bulb based on the latest LED technology. The (population) mean life of a XYZ bulb is 9 years with a population standard deviation of 1.2 years. The life of a XYZ bulb is normally distributed.

What proportion of XYZ bulbs will last more than 12 years?

Select one:

0.055

0.0456

0.0062

0.0789

The XYZ company manufactures a new kind of light bulb based on the latest LED technology. The (population) mean life of a XYZ bulb is 9 years with a population standard deviation of 1.2 years. The life of a XYZ bulb is normally distributed.

A XYZ bulb that lasts exactly 9 years, would be at what percentile?

The ABC Company manufactures printers. You have been asked to construct a confidence interval (CIE) that can be used to estimate the population mean life. You take a random sample of 100 scanners and find the sample mean life to be 10 years with a sample standard deviation of 2 years. Construct the following confidence interval estimators (CIE). You may use the values from the Z distribution since n is quite large.

Construct a 95% CI

Answer 1