Gary is specifically interested in the π = the proportion of the non-face brick. Gary would like to do a hypothesis test with the data. Gary wants to know whether or not π equals 0.22, and suspects that it may actually be different from than 0.22. Gary randomly selects 130 brick, and 39 of them are non-face (this is a different random sample than Brianna's!).

a. Gary's null hypothesis claims that p:________
b. Gary's alternative hypothesis claims that p:_______

Respuesta :

Answer:

Null hypothesis:[tex]p=0.22[/tex]  

Alternative hypothesis:[tex]p \neq 0.22[/tex]  

Step-by-step explanation:

Data given and notation

n=130 represent the random sample taken

X=29 represent the bricks with non face results

[tex]\hat p=\frac{29}{130}=0.223[/tex] estimated proportion of  interest

[tex]p_o=0.22[/tex] is the value that we want to test

[tex]\alpha[/tex] represent the significance level

Confidence=95% or 0.95

z would represent the statistic (variable of interest)

[tex]p_v[/tex] represent the p value (variable of interest)  

Concepts and formulas to use  

We need to conduct a hypothesis in order to test the claim that the true proportion is equal to 0.22 or not, the system of hypothesis are.:  

Null hypothesis:[tex]p=0.22[/tex]  

Alternative hypothesis:[tex]p \neq 0.22[/tex]  

When we conduct a proportion test we need to use the z statisitc, and the is given by:  

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

The One-Sample Proportion Test is used to assess whether a population proportion [tex]\hat p[/tex] is significantly different from a hypothesized value [tex]p_o[/tex].

Calculate the statistic  

Since we have all the info requires we can replace in formula (1) like this:  

[tex]z=\frac{0.223 -0.22}{\sqrt{\frac{0.22(1-0.22)}{130}}}=0.0826[/tex]  

Statistical decision  

It's important to refresh the p value method or p value approach . "This method is about determining "likely" or "unlikely" by determining the probability assuming the null hypothesis were true of observing a more extreme test statistic in the direction of the alternative hypothesis than the one observed". Or in other words is just a method to have an statistical decision to fail to reject or reject the null hypothesis.  

The next step would be calculate the p value for this test.  

Since is a bilateral test the p value would be:  

[tex]p_v =2*P(z>0.0826)=0.934[/tex]