Statistical Questions and Variables

Learn statistical questions, variable types.

Lesson 1 of 32 parts Practice Flashcards

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Statistical Questions

Objective: Explain statistical questions, apply the stated method, and check its conditions.

A statistical question anticipates variability in data and names a population and a measurable variable. Individual records supply observations, not necessarily distinct values. A count of responses differs from a count of categories or a count of different answers. Many people can give the same answer.

Formulas

Observations = recorded responses from measured units

Worked examples

Try itA synthetic survey asks 107 students for their favorite fruit. How many responses are collected if everyone answers once?Show answer

Step 1: The question anticipates varying preferences across students. Step 2: Each of the 107 students supplies one response. Step 3: The dataset has 107 responses, not necessarily that many distinct fruits.

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Statistical Questions

Objective: Explain statistical questions, apply the stated method, and check its conditions.

Formulas

Observations = recorded responses from measured units

Worked examples

Try itA synthetic survey asks 107 students for their favorite fruit. How many responses are collected if everyone answers once?Show answer

Variable Types

Objective: Explain variable types, apply the stated method, and check its conditions.

Categorical variables assign labels; nominal labels have no inherent order and ordinal labels do. Quantitative variables measure numerical amounts; discrete values arise from counts and continuous values from measurement. Numeric category codes remain categorical, even if stored as numbers. A numerical code for a category is not automatically a quantitative variable.

Formulas

Types: nominal, ordinal, discrete quantitative, continuous quantitative

Worked examples

Try itA synthetic class survey records bus route name. Which variable type is this?Show answer

Step 1: Decide whether values are labels or amounts. Step 2: Check ordering for labels or counting versus measurement for amounts. Step 3: This variable is nominal categorical.

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