MrDaveblev 28,285 (na) panonood 11:25 Normal Distribution: Find Probability Using With Z-scores Using the TI84 - Tagal: 5:15. Suppose the population standard deviation is 0.6 ounces. The population standard deviation, will be given in the problem. Hahaha! Thanks. Here we start with some theoretical "truth" (a true mean and standard deviation), then create some random data (following a Normal Distribution) that we imagine we just recorded. Then we can see how closely our data leads us back to the truth. Play with this so you get a good "feel" for data. Try different sample sizes, etc and see what you get.