What Z value corresponds to the lowest 25% of area under the normal curve?

2. What Z value correspond to the middle 80% of area under the normal curve?

3. What percentage of area is below a Z value of -2.58?

4. The mean of a population = 54.72, and the mean of a sample from the population = 54.92.Assuming the difference between the two values is due to chance, we can refer to the difference as sampling ______.