PSYCH 100A Lecture Notes - Lecture 4: Confidence Interval, Sampling Distribution
Document Summary
Monday, one hour before and after lecture. Distribution of the all the possible means: mu. Unbiased because it follows the true value of the population. Where the xbar is going to fall. If you take a sample xbar is the same as mu: false. It can be low or it can be higher. No effect the on the population distribution. Bigger n gets, the smaller the standard error. N-1 to make a value estimator for sample size. Confidence interval: 95% it will contain the true mean, but you are not certain that your xbar is capturing the true mean. No certainty in your xbar measurement, this process will capture the true mean 95% of the time. Bigger the n, the narrower the variance get, the precision gets up. If you want a better certainty, use the 99% confidence interval. Less precise on where it really is because the 99% confidence interval requires a larger interval than the 95% confidence interval.
