申論題

(2) (10 points) To find out whether a new serum will arrest leukemia, 9 mice, all with an advanced stage of the disease, are selected. 5 mice receive the treatment and 4 do not. Survival times, in years, from the time the experiment commenced are as follows: 
 Treatment: 2.1 5.3 1.4 4.6 0.9
No Treatment: 1.9 0.5 2.8 3.1
At the 0.05 level of significance, can the serum be said to be effective? Assume the two populations to be normally distributed with equal variances.