1. Two samples are selected at random from two independent normally distributed populations. Sample 1 has 49 observations, a mean of 10, and a standard deviation of 5. Sample 2 has 36 observations, a mean of 12, and a standard deviation of 3. The standard error of the sampling distribution of the sample mean difference, X1-bar - X2-bar is

• 0.1853
• 0.8719
• 0.7331
• 0.7602 2. In a sign test, the following information is given: number of zero differences = 3, number of positive differences = 20, and number of negative differences = 5. The value of the standardised test statistic z
• 2
• 4
• 3
• 5 3. A sample of size 200 is to be taken at random from an infinite population. Given that the population proportion is 0.60, the probability that the sample proportion will be greater than 0.58 is about:
• 0.28
• 0.42
• 0.72
• 0.58