Saturday

November 1, 2014

November 1, 2014

Posted by **br0Ok3** on Friday, October 15, 2010 at 1:15am.

TKK Products manufactures electric light bulbs in the 50-, 60-, 75-, and 100-watt range. Laboratory tests show that the lives of these light bulbs are normally distributed with a mean of 774 hr and standard deviation of 68 hr. Find the probability that a TKK light bulb selected at random will burn for the following times. Round your standard normal variable to two decimal places before using the table of values. (Give your answers to four decimal places.)

(a) less than 842 hr

(b) between 842 and 910 hr

(c) more than 638 hr

- statistics -
**PsyDAG**, Saturday, October 16, 2010 at 12:09pmZ = (score-mean)/SD

Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportions for the Z scores you obtain.

**Answer this Question**

**Related Questions**

prob and stats - –/3 points Notes Question: TanColM7 8.6.003. TKK Products ...

Physical Science, ipc - Which can you do to reduce the power consumption in your...

Math - Daphne replaced light bulbs in her mothers store.She had 3/4 of a box of ...

sTATISTICS - If light bulbs have lives that are normally distributed with a mean...

Physics - Iceland uses a voltage of 220v instead of of the US 110v. So you fly ...

statistics - If light bulbs have lives that are normally distributed with a ...

algebra 1 - On a restaurant sign, 14 light bulbs must be replaced. These light ...

Math - A consumer buys n light bulbs, each of which has a lifetime that has a ...

Math - A consumer buys n light bulbs, each of which has a lifetime that has a ...

chemistry - Light bulbs emit a broad spectrum of light; that is, they emit ...