JaJuan wants to estimate the average student GPA at his high school. He surveys 40 students and finds their average GPA to be 3.04. The population standard deviation is assumed to be 0.38. Which statement is true? JaJuan is estimating... a proportion and will use the Z-table O a mean and will use the Z-table because the population standard deviation is unknown O a mean and will use the t-table because the population standard deviation is unknown O a mean and will use the t-table because the population standard deviation is known O a mean and will use the Z-table because the population standard deviation is known a proportion and will use the t-table Question Help: Message instructor Submit