In: Statistics and Probability
Company X claims that its cell phones last significantly longer than cell phones sold by company Y. the company collected the mean length of time that cell phones from each company last before needing to be replaced.
xbar s n
company a 3.456 .85 80
Company b 2.876 .85 80
Is there sufficient evidence to reject the null hypothesis (that the mean length of time for the two population is equal) at a significance level of .01?
a. z-score=4.7657, p-value<.00001; reject the null
b. z-score=4.7657, p-value<.00001; fail to reject null
c. t-score=6.7398, p-value<.00001; reject null
d. t-score=6.7398, p-value<.00001; fail to reject the null hypothesis