An automatic coffee filling process is in control when the average amount of instant coffee that is poured into a jar is 8 oz and the standard deviation is 0.2 oz. A simple random sample of 100 jars is selected and the sample average is found to be X = 8.1 Oz. Assuming the standard deviation of the process is still 0.2 oz, is the process out of control (pouring too much coffee into the jars) after specifying the following: (i) State your null and alternative hypotheses. (ii) State your level of significance. (iii) Specify any assumptions you made while reaching at your conclusion.

MATLAB: An Introduction with Applications
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Chapter1: Starting With Matlab
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An automatic coffee filling process is in control when the average amount of instant coffee that is poured into a jar is
8 oz and the standard deviation is 0.2 oz. A simple random sample of 100 jars is selected and the sample average is found
to be x = 8.1 oz. Assuming the standard deviation of the process is still 0.2 oz, is the process out of control (pouring too
much coffee into the jars) after specifying the following:
(i) State your null and alternative hypotheses. (ii) State your level of significance.
(iii) Specify any assumptions you made while reaching at your conclusion.
The following`answers" have been proposed.
(a) (i) Ho : µ < 8, versus H1 :µ > 8.
(ii) We will use a = 0.05.
(iii) We will assume that the fill amount is normally distributed. We will reject Ho if Zstat > 1.645. In our case
Хn —8
Zstat =
= 5.0 > 1.645.
ol n
So, the evidence suggests that Họ should be rejected.
(b) (i) Ho : µ < 8, versus H1 :µ > 8.
(ii) We will use a = 0.01.
(iii) We will assume that the fill amount is normally distributed. We will reject Ho if Zstat > 1.645. In our case
Xn – 8
Zstat =
= 5.0 > 1.645.
ol yn
So, the evidence suggests that Họ should be rejected.
(c) (i) Ho : µ < 8, versus H1 :4 > 8.
(ii) We will use a = 0.001.
(iii) We will assume that the fill amount is normally distributed. We will reject Ho if Zstat > 1.96. In our case
Xn- 8
Zstat =
= 5.0 < 1.96.
ol n
So, the evidence suggests that Họ should not be rejected.
(d) (i) Ho : µ < 8, versus H1 : µ > 8.
(ii) We will use a = 0.05.
(iii) We will assume that the fill amount is normally distributed. We will reject Ho if Zstat > 0.05. In our case
Xn - 8
= 5.0 > 0.05.
Zstat =
ol yn
So, the evidence suggests that Họ should be rejected.
(e) None of the above.
The correct answer is
(а)
(b)
(c)
(d)
(e)
N/A
(Select One)
Transcribed Image Text:An automatic coffee filling process is in control when the average amount of instant coffee that is poured into a jar is 8 oz and the standard deviation is 0.2 oz. A simple random sample of 100 jars is selected and the sample average is found to be x = 8.1 oz. Assuming the standard deviation of the process is still 0.2 oz, is the process out of control (pouring too much coffee into the jars) after specifying the following: (i) State your null and alternative hypotheses. (ii) State your level of significance. (iii) Specify any assumptions you made while reaching at your conclusion. The following`answers" have been proposed. (a) (i) Ho : µ < 8, versus H1 :µ > 8. (ii) We will use a = 0.05. (iii) We will assume that the fill amount is normally distributed. We will reject Ho if Zstat > 1.645. In our case Хn —8 Zstat = = 5.0 > 1.645. ol n So, the evidence suggests that Họ should be rejected. (b) (i) Ho : µ < 8, versus H1 :µ > 8. (ii) We will use a = 0.01. (iii) We will assume that the fill amount is normally distributed. We will reject Ho if Zstat > 1.645. In our case Xn – 8 Zstat = = 5.0 > 1.645. ol yn So, the evidence suggests that Họ should be rejected. (c) (i) Ho : µ < 8, versus H1 :4 > 8. (ii) We will use a = 0.001. (iii) We will assume that the fill amount is normally distributed. We will reject Ho if Zstat > 1.96. In our case Xn- 8 Zstat = = 5.0 < 1.96. ol n So, the evidence suggests that Họ should not be rejected. (d) (i) Ho : µ < 8, versus H1 : µ > 8. (ii) We will use a = 0.05. (iii) We will assume that the fill amount is normally distributed. We will reject Ho if Zstat > 0.05. In our case Xn - 8 = 5.0 > 0.05. Zstat = ol yn So, the evidence suggests that Họ should be rejected. (e) None of the above. The correct answer is (а) (b) (c) (d) (e) N/A (Select One)
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