A quality control engineer at a potato chip company tests the bag filling machine by weighing bags of potato chips. Not every bag contains exactly the same weight. But if more than 16% of bags are over-filled then they stop production to fix the machine. They define over-filled to be more than 1 ounce above the weight on the package. The engineer weighs 94 bags and finds that 16 of them are over-filled. He plans to test the hypotheses H 0 : p = 0.11 versus H a : p > 0.11. What is the test statistic?

Respuesta :

Answer:

The test statistic is z = 1.865.

Step-by-step explanation:

The test statistic is:

[tex]z = \frac{X - \mu}{\frac{\sigma}{\sqrt{n}}}[/tex]

In which X is the sample mean, [tex]\mu[/tex] is the value tested at the null hypothesis, [tex]\sigma[/tex] is the standard deviation and n is the size of the sample.

H0: p = 0.11

This means that 0.11 is tested at the null hypothesis, and so:

[tex]\mu = 0.11[/tex]

[tex]\sigma = \sqrt{0.11*0.89} = 0.3129[/tex]

The engineer weighs 94 bags and finds that 16 of them are over-filled.

This means that:

[tex]n = 94, X = \frac{16}{94} = 0.1702[/tex]

What is the test statistic?

[tex]z = \frac{X - \mu}{\frac{\sigma}{\sqrt{n}}}[/tex]

[tex]z = \frac{0.1702 - 0.11}{\frac{0.3129}{\sqrt{94}}}[/tex]

[tex]z = 1.865[/tex]

The test statistic is z = 1.865.