Answer
The decision rule is
Fail to reject the null hypothesis
The conclusion is
There is no sufficient evidence to conclude that the machine is underfilling the bags
Step-by-step-explanation:
From the question we are told that
The population mean is [tex]\mu = 420.0 \ g[/tex]
The sample size is n = 33 bags
The sample mean is [tex]\= x = 417.0 \ g[/tex]
The level of significance is [tex]\alpha = 0.01[/tex]
The variance is [tex]\sigma^2 = 576.0[/tex]
The null hypothesis is [tex]H_o : \mu = 420[/tex]
The alternative hypothesis is [tex]H_a : \mu < 420[/tex]
Generally the standard deviation is mathematically represented as
[tex]\sigma = \sqrt{\sigma^2}[/tex]
=> [tex]\sigma = \sqrt{576 }[/tex]
=> [tex]\sigma = 24[/tex]
Generally the test statistics is mathematically represented as
[tex]z = \frac{ \= x - \sigma }{ \frac{\sigma}{\sqrt{n} } }[/tex]
=> [tex]z = \frac{417 - 420 }{ \frac{24}{ \sqrt{ 33} } }[/tex]
=> [tex]z = -0.71807[/tex]
From the z table the area under the normal curve to the left corresponding to -0.71807 is
[tex]p-value = P(Z < -0.71807 ) = 0.23636[/tex]
Generally looking at the values we see that
[tex]p-value > \alpha[/tex] , hence
The decision rule is
Fail to reject the null hypothesis
The conclusion is
There is no sufficient evidence to conclude that the machine is underfilling the bags
