# Hypothesis Testing for population mean

A flashlight company claims that the new bulb in its heavy duty flashlight will average 246 hours of light. A statistics student decides that he/she wants to test this claim at a 5% level of significance to determine if there is evidence to support the claim. The student randomly selects and tests 15 flashlight bulbs and records how long the bulb lasts until it burns out. Assume the life of a bulb is normally distributed with a standard deviation of 7.4 hours. The data is in the table below:

Trial 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

Hrs: 246 224 231 242 237 240 243 236 239 255 256 239 247 231 253

https://brainmass.com/statistics/z-test/hypothesis-testing-for-population-mean-646732

#### Solution Preview

Since the population standard deviation is known to be sigma=7.4 hours, it would be appropriate to conduct a one-sample Z-test.

Null hypothesis Ho: the flashlight will average 246 hours of light

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#### Solution Summary

The solution consists of all details of conducting a one-sample Z-test for population mean.