Honors Stats

Objectives: SWBT: Identify the context of data, or realize that some parts of the context are not provided. Identify the variables in a data set, and classify which type each one is.

Classroom Survey Where you surprised by anything? Struggled with anything? How did you choose to represent the data?

Classroom Survey Bedtime Time you fell asleep or time you got into bed or time you turned off the lights? Shoe Size Men’s 7 and Women’s 7 are VERY different. What if someone was from the UK?

What is Data? Systematically recorded information, whether numbers or labels, together with its context. Why does the context matter?

Context Matters 12, 15, 20, 30, 72

Context Matters 12, 15, 20, 30, 72 If it’s scores on a test we feel differently than if it’s the numbers on five people’s football jerseys.

Context 5 Ws+H. Who was measured What was measured How the data was collected Where the data was collected When/Why the study was performed When given data, look for these 5Ws!

Example One A Consumer Reports article on energy bars gave the brand name, flavor, price, number of calories, and grams of protein and fat. Give the context

5Ws Who? What? How? Where? When? Why?

5Ws Who? Energy Bars What? Brand Name, Flavor, Price, Calories, Protein, Fat How? Not specified… hmmm. Is data collected from companies? From labels? Where? Not specified When? Not specified. Why? To inform potential consumers.

Problems: Example One 1. Not enough information is given! We have no where or when or how! 2. Bigger Problem? UNITS! What units was the price? Was it dollars, pounds, euro?

UNITS Things need to be measured with the same units! Ex: Hard to compare male/female shoe sizes because they are different! Is price considered in American dollars, pounds, euro? Bedtime– what is considered bedtime? In order to have data that makes sense you need to specify the UNITS.

Context Lacking Quotes from your graphs handed in on Friday: “From this graph it is obvious that most students don’t carry money on them.” “The latest bedtime was 3 am and the average bedtime was 11 pm.” “(This is a) T-Chart graphing all the students on the left, and whether they have eaten sushi or not.”

Context Lacking (continued) The most common time for high school students to go to bed is 11 pm. Everyone estimated that Mr. Delery was in his high 20s, low 30s. Most people go to bed around 11:00, and nobody went to bed before 10:00.

Lesson? When giving a context- be specific :D

Variables Definition: The characteristics recorded about each individual case. Note: In stats certain terms you have seen in math will be defined differently! Stats has its own vocabulary!

Two Types of Variables Categorical Variables that names categories (whether with words or numerals) Ex: Grade, Country of origin

2 Types of Variables: Quantitative Variables in which the numbers act as numerical values. Quantitative variables must have a UNIT. Ex: Height, age, distance

Example One Revisited A Consumer Reports article on energy bars gave the brand name, flavor, price, number of calories, and grams of protein and fat. What are the variables? Which type are they?

Example One: Variables Categorical Variables: Brand Name, Flavor Quantitative Variables: Price (US $$), number of calories (calories), protein (grams), fat (grams)

Types can be Tricky…. What type a variable is can often be rather easy to figure out. YET. Notice that the type mostly depends on how we display and analyze the data Ex: Age If we use actual age it is quantitative If we just use basic categories like child, adult, senior then it is categorical.

Example Two: A report on the Boston Marathon listed each runner’s gender, country of origin, age and time. Context? Variables?

Example Two: Who? What? When? Where? Why?

Example Two: Who? Boston Marathon Runners What? Gender, Country, Age, Time When? Not specified Where? Boston, MA Why? Race result reporting How? Unknown….

Example Two: Variables Categorical: Quantitative:

Example Two: Variables Categorical: gender, country of origin Quantitative: age (years), time (hours, minutes, seconds)

Practice Try some on your own or in your groups– at least check your answers with your group members.

Exit Ticket A study was conducted to compare the abilities of men and women to preform strenuous tasks required of a shipboard firefighter. The student reports the pulling force (in Newtons) that a firefighter was able to exert in pulling the starter cord of a P-250 water pump. The study also gives the weight and gender of the firefighters. Give context/identify variables.