1. the quality control manager at a light-bulb factory needs to estimate the mean life of a new type of light-bulb. the population standard deviation is assumed to be 60 hours. a random sample of 32 light-bulbs shows a sample mean life of 490 hours. construct and explain a 95% confidence interval estimate of the population mean life of the new light-bulb.

The 95% confidence interval estimate of the population mean life of the new light-bulb is (469.21 hours, 510.79 hours).

This confidence level means that we are 95% sure that the true population mean life of the new light bulb is in this interval.

Step-by-step explanation:

We have that to find our level, that is the subtraction of 1 by the confidence interval divided by 2. So:

Now, we have to find z in the Ztable as such z has a pvalue of .

So it is z with a pvalue of , so

Now we find M as such:

In which is the standard deviation of the population and n is the length of the sample. So:

The lower end of the interval is the mean subtracted by M. So it is 490 - 20.79 = 469.21 hours.

The upper end of the interval is the mean added to M. So it is 490 + 20.79 = 510.79 hours.

The 95% confidence interval estimate of the population mean life of the new light-bulb is (469.21 hours, 510.79 hours).

This confidence level means that we are 95% sure that the true population mean life of the new light bulb is in this interval.

answer 1 : option "c"

answer 2 : option "d"

answer 3 : option "b"

answer 4 : option "d"

answer 5 : option "b"

answer 6 : option "a"

answer 7 : option "c"

answer 8 : option "d"

answer 9 : option "c"

answer 10 : option "d"

answer 11 : option "c"

answer 12 option "b"

answer 13 option "c"

answer 14 option "c"

answer 15 option "d"

answer 16 option "a"

answer 17 option "b"

answer 18 option "c"

answer 19 option "a"

answer 20 option "a"

answer 21 option "c"

d

she will travel a distance in the range of 3 - 11 miles