Welcome Back and Welcome to Honors Statistics! Mr. Calise (Rm: 306) 2017 - 2018 Chapter 1: Exploring Data Section 1.1 Introduction The Practice of Statistics, 2nd edition STARNES, YATES, MOORE

We study statistics because… … anecdotal evidence is not reliable. … we don’t wish to be lied to. … spotting trends helps us make good decisions Simply, we study statistics because we want to make sense of the world. CASA, AP Stats 05-06, Section 1.1.1

What is Statistics?

What is going on here! Take your piece of the graph and try to make one complete graph by finding the other pieces that go with your piece.

Puzzle Exercise Once you have completed your graph, discuss with the other members in your group what data your graph represents. Your options are as follows: A) The months all OMHS students were born B) The distribution of GPA’s at Harvard C) The distribution of SAT scores in Maryland D) The distribution of salaries for students right out of college

Is the data convincing? One of the main things we will be looking at this year is how to determine whether or not we have enough data to make a conclusion about some hypothesis.

Stats Starts Here According to 100% of people surveyed, this is the greatest class ever offered in college. List of people surveyed: ME

The Exam (FICTIONAL DATA) The class average last semester was a 94 on the final exam. It was out of 500 points!!!! A group of individuals averaged a 78% on an algebra exam…… The group of individuals were 7 year olds… Or…the group of individuals were Algebra teachers!

Dream Job The average salary at a company that has 25 employees is $8,500,000 per year. Would you like to be hired by this company? The CEO makes $212,400,000 per year… The other 24 employees Average $4,166.67 per/year

The “W’s” To provide context we need the W’s Who What (and in what units) When Where Why (if possible) and How of the data. Note: the answers to “who” and “what” are essential.

WEBQUEST Types of Variables

Vocabulary Individuals – objects in a data set. Sometimes referred to as x1, x2, x3, etc. Variable – any characteristic of an individual Thinking of the individuals in this room, what might some of their characteristics? CASA, AP Stats 05-06, Section 1.1.1

Categorical vs. Quantitative Categorical variables places individuals in one of several groups. Quantitative variables take numerical values for which arithmetic operations like adding make sense. Of the variables describing the members of the class, which are categorical and which are quantitative? CASA, AP Stats 05-06, Section 1.1.1

Examples Q C Time it takes to get to school Height in inches Number of shoes owned Gender Hair color Age of Oscar winners Temperature of a cup of coffee Type of pain medication Jellybean flavors Hours on Social Media Q C

Distribution “The distribution of a variable tells us what values the variable takes and how often it takes these values.” How distributions differ between categorical and quantitative variables? CASA, AP Stats 05-06, Section 1.1.1

Chapter 1: Exploring Data Section 1.1 Displaying Distributions with Graphs The Practice of Statistics, 2nd edition STARNES, YATES, MOORE

Bar Charts VS. Pie Charts Bar Charts and Pie Charts are used when displaying Categorical data, because they just show counts or percents. Bar Charts are broken up into categories and the bars are NOT connected. Pie Charts also show counts or percents but are displayed in a circle broken up into corresponding regions.

Attributes of a “good” bar-chart Title Axis Labels Consistent Scale

Pie Charts Pie Charts can be used to show the counts in each category or the actual percent breakdown for each category.

Describing Distributions Shape: What shape does the data take Center: Where is the middle of the data (middle is intentionally vague) Spread: How far apart the data is from each data point. Are there Outliers? Outliers are atypical data points Outliers fall outside the overall pattern of the graph CASA, AP Stats 05-06, Section 1.1.1

Describing Shape Uniform Bell Symmetric Skew Bimodal CASA, AP Stats 05-06, Section 1.1.1

Uniform 1 13489 2 3 4 5 6 7 8 9 10 CASA, AP Stats 05-06, Section 1.1.1

Bell 1 2 13 3 135 4 1357 5 135579 6 1355779 7 8 9 10 CASA, AP Stats 05-06, Section 1.1.1

Skew 1 2 1357 3 1355779 4 135579 5 6 7 13 8 9 10 CASA, AP Stats 05-06, Section 1.1.1

Bimodal 1 2 1357 3 1355779 4 135579 5 6 13 7 8 9 10 CASA, AP Stats 05-06, Section 1.1.1

HOMEWORK Collect at least 30 pieces of categorical data and create a bar chart. Describe the shape of the bar chart. GRADED ASSIGNMENT