Test of equality of normal means in the absence of independent estimator of variance

Let X1,…, Xn be normally and independently distributed with means 0n,…0n and a common variance. Thus there are n observations and n+1 unknown parameters. A test of the null hypothesis that the Qs are all zero and the alternative that the vector (0,0) lies in a convex cone with its vertex at the origin is considered in this paper. It is shown that under a mild condition the likelihood ratio test is possible. The ordinary one sided t-test belongs to the class of tests considered in this paper. The hypothesis of equality of means against the simple order alternative can be tested in certain cases.