In: Statistics and Probability
LED headlights on cars seem to becoming increasingly popular, so I thought I would make my problem about that. I believe that the proportion of car owners who have LED headlights is higher than the proportion of car owners to use regular non-LED headlights now, (according to data from 2019) versus in 2010. During two independent surveys, one survey noted that 355 out of 600 car owners had LED headlights in 2020, while in 2010, 250 out of 600 car owners had LED headlights.
Test this hypothesis using the significance level of 0.05.
For sample 1, we have that the sample size is N1=600, the number of favorable cases is X1=355, so then the sample proportion is
For sample 2, we have that the sample size is N2=600, the number of favorable cases is X2=250, so then the sample proportion is
The value of the pooled proportion is computed as
Also, the given significance level is α=0.05.
(1) Null and Alternative Hypotheses
The following null and alternative hypotheses need to be tested:
Ho:
Ha:
This corresponds to a right-tailed test, for which a z-test for two population proportions needs to be conducted.
(2) Rejection Region
Based on the information provided, the significance level is α=0.05, and the critical value for a right-tailed test is zc=1.64.
The rejection region for this right-tailed test is R={z:z>1.64}
(3) Test Statistics
The z-statistic is computed as follows:
(4) The decision about
the null hypothesis
Since it is observed that z=6.062>zc=1.64, it is then concluded that the null hypothesis is rejected.
Using the P-value approach: The p-value is p=0, and since p=0<0.05, it is concluded that the null hypothesis is rejected.
(5) Conclusion
It is concluded that the null hypothesis Ho is rejected. Therefore, there is enough evidence to claim that population proportion p1 is greater than p2, at the 0.05 significance level. Hence the proportion of car owners who have LED headlights is higher than the proportion of car owners to use regular non-LED headlights now, (according to data from 2019) versus in 2010.
Every upvote matters! So please do upvote if you are satisfied! Let me know in the comments if anything is not clear. I will reply ASAP!