PSY 207 Lecture Notes - Lecture 5: Standard Deviation, Normal Distribution, Statistical Inference
Document Summary
Ch 5: z-scores and location in a distribution. In statistics, when we plot a smooth curve instead of a histogram (or frequency polygon), we are plotting a probability density curve. Histogram - shows the frequency of the variable plotted on the x axis. Probability density curve - shows the probability or likelihood of the variable plotted on the x axis. Some different probability density curves: doesn"t need to be normal, but when it is, it is called a normal density curve. Normal density curve: there are many possible normal density curves, each having a different mean and standard deviation. Normal density curve: means: normal curves will have different means if they are centered around different values. It"s not that we"re squeezing the data to t the shape of a normal curve: mean becomes 0, raw scores become z-scores (deviation scores on standard normal curve)
