STP 231 Lecture Notes - Lecture 19: Tanning Bed, Central Limit Theorem, Sampling Distribution
Document Summary
For random sample of sufficiently large size, the sampling distribution of the sample mean is approximately normal with mean and standard deviation /sqrt(n) Randomization: data values must be sampled randomly. Independence assumption: the sampled values must be mutually independent. 10% rule: the sample is no more than 10% of the population. The sample size must be at least 30. If the population is normally distributed, you do not need to worry about sample size. If we were to draw a curve to fit the information, it will be a symmetric normal curve. Each number represents a sample mean of one of the many samples selected. When we put all of these sample means together, we make the sample normal distribution curve. A health club recently added tanning booths in addition to a weight room, pool, and racquetball courts. For insurance purposes, an employee maintains careful records of the length of time each member spends in a tanning booth.
