Now the zookeeper doesn't know that and so instead, they're trying to estimate it by sampling 30 days. So let's think about it this way. Let's say that this is the true population mean, the true mean amount of food that an elephant will eat in a day. What the zookeeper can try to do is, well they take a sample and in this case, they took a sample of 30 days and they calculated a sample statistic, in this case the sample mean of 350 kilograms. I don't know if it's actually to the right of the true parameter but just for visualization purposes, let's say it is. So let's say sample mean and this is their first sample. It was 350 kilograms and then using this, using the sample, they were able to construct a confidence interval from 341 to 359 kilograms and so the confidence interval, I'll draw it like this.