Statistical Questioning Lesson 8.01

After completing this lesson, you will be able to say: I can recognize and write a statistical question. I can recognize that data can have variability as a result of the question. I can explain that a set of data collected to answer a statistical question has a distribution.

Collecting Data Data: Collected information on a given topic data can help someone learn more about a particular topic and make conclusions. Ways to collect data: Surveys Research Interviews

Statistical Process Statistical process: A four-step process that helps someone collect, organize, display, and analyze data on a given topic. Steps of the Statistical Process 1. Form a question that can be answered by data. 2. Design and implement a plan that collects the appropriate data. 3. Analyze the data using graphical and numerical methods. 4. Interpret and compare the data.

Statistical Process Step 1 of the statistical process: Form a question that can be answered by data Statistical question: A question that guides research by defining the population of a given topic and that anticipates variability in the collected data. 3 Characteristics of a Statistical Question Allows for clear responses Includes a specific population Anticipates variability of the data

Characteristics of a Statistical Question Allows for clear responses There are many different types of data that can be collected from statistical questions. Two of these types are categorical data and numerical data. In the following examples, notice participants had to select an answer from a list, allowing for clear responses

Characteristics of a Statistical Question Includes a specific population  A statistical question must include a population.  A population defines the group being studied.  When you collect data, you can either survey the entire population or a sample of the population. Bad example: How many hours of chores were done last night? Survey example: How many hours of chores did you do last night? Best example: How many hours of chores did students at Timber Middle School do last night?

Characteristics of a Statistical Question Anticipates variability of the data A statistical question must expect variability in data. This means it should result in a variety of responses, not just one or two responses. This is most important. Yes or no questions do not provide variability. Bad example: How many letters are in Mr. Smith’s last name? Bad example: Do you know how many letters are in your teacher’s last name? Good example: On average, how many letters are in sixth-grade teachers’ last names?

Statistical Questions - Examples Let’s take a look at a few questions to determine whether they are statistical questions. This question is not a statistical question because it has a single answer. Either Sarah or Tim is taller. Because there is only one response, this question does not have variability. This is a statistical question. The population is all the students in the class. You can collect data on the height of each person in the class. Because each person could be a different height, the question anticipates variability.

Statistical Questions – Try It

Check your work

How Does Data Look? Whenever data are collected to answer a statistical question, the data have a distribution. The distribution of data simply shows how often each value in the data set occurs. The type of question, who you ask, and how you ask it can all affect the distribution of the data collected. A distribution is described by its center, spread, or shape.

Center Center: When describing a distribution, the average or middle of a data set. The center of the data is around the values of 1 and 2. Remember, the data center is not always located in the middle of the table.

Spread Spread: When describing a distribution, the variability of a data set. The data are spread between the values of 0 and 8.

shape Shape: When describing a distribution, the visual look of a data set. The shape of these data rises at the lower values and falls around the higher values.

Now that you completed this lesson, you should be able to say: I can recognize and write a statistical question. I can recognize that data can have variability as a result of the question. I can explain that a set of data collected to answer a statistical question has a distribution.