Barnard Statistics Concepts Practice Test

The table that shows proportions under the normal curve is the Unit Normal Table, also called the Z-table. It lists P(Z ≤ z) for the standard normal distribution (mean 0, standard deviation 1). To use it with any normal variable X ~ N(μ, σ²), standardize with z = (X − μ)/σ and then read P(Z ≤ z) from the table. This lets you convert a z-score into its associated probability under the bell curve.

The Central Limit Theorem is about why sample means tend to be normal under certain conditions, not a table of probabilities. Probability is the broad concept of likelihood, not a specific table. Distribution of Sample Means describes the sampling distribution of averages, not the standard-normal probabilities captured by the Z-table.