Temperatures A towns January high temperatures average 36F with a standard deviation of 10, while in July the mean high temperature is 74 and the standard deviation is 8. In which month is it more unusual to have a day with a high temperature of 55? Explain.

Note: Lecture 17 gives example problems for using the probability table for standard normal probabilities Introducing sampling distribution of statistic- Probability model of sample mean, and the central limit theorem: - Fundamental question: How do we measure if a statistic of a study indicates a “real” effect as opposed to a result of random variation o To answer this, we need to look at the sampling distribution – the probability distribution of all possible values of a statistic (from repeated samples of same size from the same population) o The principle: to imagine all possible samples that could have been obtained