The management of ABC Industries is considering a new method of assembling its golf cart. The present method requires 42.3 minutes, on the average, to assemble a cart. The mean assembly time for a random sample of 24 carts, using the new method, was 40.6 minutes, and the standard deviation of the sample was 2.7 minutes. Using a 0.1 level of significance, can we conclude that the assembly time using the new method is faster? Use only the P-Value approach. State H0 and Ha (20 pts)

Respuesta :

Answer:

Null hypothesis:[tex]\mu \geq 42.3[/tex]  

Alternative hypothesis:[tex]\mu < 42.3[/tex]  

[tex]t=\frac{40.6-42.3}{\frac{2.7}{\sqrt{24}}}=-3.085[/tex]    

The degrees of freedom are given by:

[tex]df=n-1=24-1=23[/tex]  

Then the p value can be calculated with this probability:

[tex]p_v =P(t_{(23)}<-3.085)=0.0026[/tex]  

If we compare the p value and the significance lvel of 0.1 we see that the p value is lower than the signficance level we can reject the null hypothesis and we can conclude that the the assembly time using the new method is faster

Step-by-step explanation:

Information given

[tex]\bar X=40.6[/tex] represent the sample mean for the new method

[tex]s=2.7[/tex] represent the sample standard deviation

[tex]n=24[/tex] sample size  

[tex]\mu_o =42.3[/tex] represent the value that we want to test

[tex]\alpha=0.1[/tex] represent the significance level

t would represent the statistic

[tex]p_v[/tex] represent the p value

System of hypothesis

We want to verify if  the assembly time using the new method is faster, the system of hypothesis would be:  

Null hypothesis:[tex]\mu \geq 42.3[/tex]  

Alternative hypothesis:[tex]\mu < 42.3[/tex]  

The statistic for this case is given:

[tex]t=\frac{\bar X-\mu_o}{\frac{s}{\sqrt{n}}}[/tex]  (1)  

The statistic would be given by:

[tex]t=\frac{40.6-42.3}{\frac{2.7}{\sqrt{24}}}=-3.085[/tex]    

The degrees of freedom are given by:

[tex]df=n-1=24-1=23[/tex]  

Then the p value can be calculated with this probability:

[tex]p_v =P(t_{(23)}<-3.085)=0.0026[/tex]  

If we compare the p value and the significance lvel of 0.1 we see that the p value is lower than the signficance level we can reject the null hypothesis and we can conclude that the the assembly time using the new method is faster