A random sample of size n = 68 is taken from a population with mean = 12.9 and standard deviation = 7. [You may find it useful to reference the z table.] a. Calculate the expected value and the standard error for the sampling distribution of the sample mean. (Negative values should be indicated by a minus sign. Round "expected value" to 1 decimal place and "standard error" to 4 decimal places.) b. What is the probability that the sample mean is less than 13? (Round z value to 2 decimal places, and final answer to 4 decimal places.) c. What is the probability that the sample mean falls between 13 and 12? (Do not round intermediate calculations. Round "z" value to 2 decimal places and final answer to 4 decimal places.).