To understand the critical nature of sleep to our children's growth and development, we need to understand more about what sleep does, what healthy sleep is, and what happens when children do not get either the right amount of sleep, the best quality sleep, or both.lthough this may seem apparent, many of us actually do not allow our children to get the critical sleep they need to develop and function properly. It's certainly not something we do on purpose. As a matter of fact, we often don't think much of it, and that is the problem.
Sample Mean. The sample mean is the average of all the items in a sample (a group of observations). The following is the formula for the sample mean x of a set {x1, x2, ..., xn} of n observations from a given distribution: The population mean is the average of all the items in a population. Because a population is usually very large or unknown, the population mean is usually an unknown constant. An estimate of the population mean is the sample mean.
Sample: A sample is a portion of a population selected for further analysis. How samples are obtained or types of sampling will be studied in lesson 7. Most any of the examples above for population could serve as a sample for the next higher level data set. The plural of statistic just above is another basic meaning of statistics.