The lifetimes in hours of two brands of batteries follow normal distributions with means (miu x, miu y) respectively and unequal variances. Independent random samples of 5 batteries from each brand are taken and the following data is observed. n= 40

Brand	n	Sample mean	sample variance
A	40	210	840
B	40	190	760

Test at the 5% significance level the null hypothesis that the means are equal against the alternative that they are not. The value of the test statistic and the decision are