1.Assuming the population variances are known, the variance of thedistribution of differences between twoindependent population means is ________.

		the sum of the two sample sizes for each population
		the sum of the two variances of the two sampling distributions
		the sum of the two means
		the sum of the two standarddeviations of the two sampling distributions

2. Consider a two-tailed test with a level of confidence of 81.70%. The z-value is _______.

		2.00
		0.89
		2.66
		1.33