#AP Psychology Study Guide: Statistics & Research Methods

Hey there, future AP Psych superstar! Let's break down the world of statistics and research methods. This guide is designed to be your go-to resource the night before the exam. We'll make sure you're not just memorizing, but understanding the concepts. Let's get started! 🚀

#Types of Statistics

It's all about how we use numbers! There are two main types of statistics:

• Descriptive Statistics: These are all about describing your data. Think of it as summarizing the key features of your data set. We'll be focusing on this in this study guide. 📊
• Inferential Statistics: This is where you start making inferences or drawing conclusions about a larger population based on your sample data. It's like detective work! 🕵️‍♀️

#Summarizing Data

So, you've got data... now what? We use graphs and descriptive statistics to make sense of it all. 📈

#Measures of Central Tendency

These tell you about the 'center' of your data. Think of them as the typical or average values.

• Mean: The average. Add up all the values and divide by the total number of values. The mean is sensitive to outliers. 💡

  • Formula: $\frac{\sum x}{n}$ (where $\sum x$ is the sum of all values and $n$ is the number of values)

• Median: The middle value when the data is ordered. Not affected by outliers. Perfect for skewed data! 🎯

• Mode: The most frequently occurring value. A dataset can have one mode (unimodal), two modes (bimodal), or more (multimodal). 👯

Example: Let's use the dataset: 5, 10, 5, 7, 12, 15, 18

• Mode: 5 (appears twice)
• Mean: (5 + 10 + 5 + 7 + 12 + 15 + 18) / 7 = 10.29
• Median: First, order the data: 5, 5, 7, 10, 12, 15, 18. The median is 10. ### Measures of Variation

These tell you how spread out your data is. 📏

• Standard Deviation: How much the values in a dataset deviate from the mean. A low standard deviation means data is clustered close to t...