1. Which of the following are true about the standard normal distribution? Select all that apply. Skewed to the right Mean of 0 Standard deviation of 1 Also known as the z distribution Shape is unknown 2. Data concerning life expectancy were collected from 199 countries. The mean life expectancy was 71 years with a standard deviation of 9 years. Compute the z score for a country with a life expectancy of 78 years. Round your final answer to three decimal places. 3. Research question: Is the population mean different from 50? Ho: u = 50 Ha: ul # 50 In a large sample, a mean of 57.91 was observed. The standard error was 4.652 Compute the test statistic using the general form of a test statistic: Round your final answer to three decimal places. 4. Ho : Ma-Hub=0 Ha: Ha-Hb>0 In a large sample, X a-X b= 7.738 with a standard error of 2.142 Compute the test statistic using the general formula for a test statistic: Round your final answer to three decimal places