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 15% 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 100 bags and finds that 21 of them are over-filled.

He plans to test the hypotheses: H0: p = 0.15 versus Ha: p > 0.15 (where p is the true proportion of overfilled bags).

What is the test statistic?

Z = 1.68
Z = -1.68
Z = 4
Z = -1.47

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ChiKesselman ChiKesselman · Answer 1 · 2020-02-19T05:21:58+01:00

Answer:

Option A) 1.68

Step-by-step explanation:

We are given the following in the question:

Sample size, n = 100

p = 15% = 0.15

Number of bags overfilled , x = 21

First, we design the null and the alternate hypothesis

[tex]H_{0}: p = 0.15\\H_A: p > 0.15[/tex]

Formula:

[tex]\hat{p} = \dfrac{x}{n} = \dfrac{21}{100} = 0.21[/tex]

[tex]z = \dfrac{\hat{p}-p}{\sqrt{\dfrac{p(1-p)}{n}}}[/tex]

Putting values, we get,

[tex]z = \dfrac{0.21-0.15}{\sqrt{\dfrac{0.15(1-0.15)}{100}}}\\\\z = 1.68[/tex]

Thus, the correct answer is

Option A) 1.68