Mathematics: A testing engineer in a light bulb factory is planning a study to estimate the average life of a large shipment of light bulbs. The engineer wants to estimate the average life within plus or minus 16 hours with 95 percent confidence. Assuming a process standard deviation of 90 hours, determine the sample size for this study. a. 7 b. 43 c. 58 d. 122

A testing engineer in a light bulb factory is planning

Ответ:

labrandonanderson00

23.01.2022

d. 122

Step-by-step explanation:

Formula to find sample size : $n=\left ( \dfrac{\sigma\times z}{E} \right )^2$ , where $\isigma$ = prior population standard deviation, z= Critical z-value for confidence level and E = Margin of error.

As per given ,

$\sigma=90\ hours\\\\E=\pm16\ hours$

Also , for 95% confidence level , z-value = 1.96

Now , Required sample size would be

$n=\left ( \dfrac{90\times1.96}{16} \right )^2\\\\=\left(11.025\right)^2\\\\=121.550625\approx122$

Hence, the required sample size =122

Thus , the correct option is d. 122.

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Ответ:

larissa1013

11.04.2020

Mathematics

€1333.33

Step-by-step explanation:

Al Tom ratio to Joe=5:4

Joe gets 1.5 times the amount Al gets

€3000 in the ratio 5:4

Al share

5/9×3000

=€1666.67

Joe share

4/9×3000

=€1333.33

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