Answer Happy

Suppose that we want to estimate the mean score on a nationwide examination in biology, and for this purpose we choose a random sample of exam scores. The sample we choose has a mean of 509 and a standard deviation of 75. For each of the following sampling scenarios, determine which test statistic is appropriate to use when making inference statements about the population mean. (In the table, Z refers to a variable having a standard normal distribution, and t refers to a variable having a t distribution.) Sampling Scenario Z t could use either Z or unclear t O O (1) The sample has size 13, and it is from a normally distributed population with unknown standard deviation. (2) The sample has size 12, and it is from a normally distributed population with a known standard deviation of 75. (3) The sample has size 16, and it is from a population with a distribution about which we know very little. O O O O O (4) The sample has size 110, and it is from a non- normally distributed population. о O O (5) The sample has size 105, and it is from a non- normally distributed population with a known standard deviation of 75. O o O o Х ?