A normal distribution can be converted into standard normal distribution by replotting the probability density as a function of the z score. This simple conversion tells us how many standard deviations away from the mean each value lies, enabling direct comparison of data sets. Additionally, it provides an easy way to find the probability of an event occurrence by calculating the cumulative area from the left to the z score value. Consider the birth weight of babies in a hospital. What is the probability of having a birth weight below 4 kg? First, the appropriate z score corresponding to 4 kg birth weight is calculated, which is 1.25. Now, using the z table that provides the probability values, one can obtain the probability associated with 1.25. In the left column of the z table, locate the first decimal,1.2. Then locate the column for the second decimal place, 0.05. The number at the intersection, 0.8944, gives the probability of babies having a birth weight of less than 4 kg.