UC Davis STA 13: Lecture 1 Flashcards

Questions and Answers

What is statistics?

The science of data which classifies, collects, organizes information to help people make decisions of uncertainty.

What is a population? Provide an example.

A larger body of measurements. Example: Gonzalez Ceja family.

What is a sample? Provide an example.

A small set of measurements drawn from a population. Example: Lopez family.

What is a variable? Provide an example.

A factor that changes over time. Example: Hair color. Signup and view all the answers

What is an experimental unit? Provide an example.

The individual or object on which a variable is measured. Example: One person, animal, light bulb. Signup and view all the answers

What is a measurement? Provide an example.

The result when a variable is actually measured on an experimental unit. Example: The time until the light bulb burns. Signup and view all the answers

What is data? Provide an example.

A set of measurements from a sample or a population. Example: The overall information that the light bulb burned in 30 minutes. Signup and view all the answers

Describe the variable, experimental unit, and measurements: Brown, Black, Blonde.

Variable: Hair color; Experimental unit: Person; Measurements: Brown, Black, Blonde. Signup and view all the answers

What is univariate data? Provide an example.

One variable is measured on a single experimental unit. Example: The grade on a test that Fatima received. Signup and view all the answers

What is bivariate data? Provide an example.

Two variables being measured on a single experiment. Example: Fatima and Lili's test scores. Signup and view all the answers

What is multivariate data? Provide an example.

More than two variables are measured on a single experiment. Example: The whole class test scores. Signup and view all the answers

What is a qualitative variable? Provide an example.

Measures a quality or characteristic on each experimental unit. Example: A car can be a Honda, Lexus, or Ford. Signup and view all the answers

What is a quantitative variable? Provide an example.

Measures a numerical quantity on each experimental unit. Example: The number of cars in the parking lot. Signup and view all the answers

What is a quantitative discrete variable? Provide an example.

One that can only take specific numeric values such as whole integers. Example: Population in a particular area of the US. 4,000. Signup and view all the answers

What is a quantitative continuous variable? Provide an example.

One that can take any value including fractions or decimals. Example: Time to complete an exam. 1:50. Signup and view all the answers

What is a bar graph? Provide an example.

Used to represent the quantitative variable, where the height represents frequency. Signup and view all the answers

What is a pie chart? Provide an example.

Used to represent a quantitative variable with a circle divided into slices proportional to frequency. Signup and view all the answers

What is a line chart? Provide an example.

Used to measure a single quantitative variable over time, called a time series. Signup and view all the answers

What is a dot plot? Provide an example.

The simplest graph for quantitative data, that plots measurements on a horizontal axis. Signup and view all the answers

What is a stem and leaf plot? Provide an example.

A simple graph for quantitative data that uses the numerical values of each data point. Example: 47, 20, 23, 6, 100; stem 4, leaf 7. Signup and view all the answers

What is mound shape symmetrical distribution?

Mirror image, exactly even and alike. Signup and view all the answers

What is skewed right distribution?

Positive. Median > mean; a few unusually large measurements. Signup and view all the answers

What is skewed left distribution?

Negative; the peak of the data is to the right side of the graph, with few data points on the left. Signup and view all the answers

What is bimodal?

Two peaks. Signup and view all the answers

What is a relative frequency histogram?

A bar graph for quantitative data where the height of the bar shows frequency. Signup and view all the answers

What are subintervals?

Classes. Signup and view all the answers

What are the ages of 50 tenured faculty at a state university?

Look at notes and practice. Signup and view all the answers

Study Notes

Statistics Fundamentals

Statistics is the science of data that helps in classifying, collecting, and organizing information for decision-making under uncertainty.

Population and Sample

A population is a larger body of measurements, for example, the Gonzalez Ceja family.
A sample is a smaller set drawn from a population, such as the Lopez family.

Variables and Measurements

A variable is a factor that changes over time, like hair color.
An experimental unit is the individual or object on which a variable is measured, such as a person or a light bulb.
A measurement is the result obtained when a variable is measured on an experimental unit, for instance, the time until a light bulb burns out.
Data represents a set of measurements, for example, the light bulb burned for 30 minutes.

Types of Data

Univariate data involves one variable measured on a single experimental unit, such as Fatima’s test grade.
Bivariate data includes two variables measured on a single experiment, like Fatima and Lili’s test scores.
Multivariate data captures more than two variables measured in one experiment, such as the entire class's test scores.

Variables Classification

A qualitative variable measures characteristics on each experimental unit, e.g., types of cars like Honda, Lexus, or Ford.
A quantitative variable measures numerical quantities, such as the number of cars in a parking lot.
Quantitative discrete variables can only take specific numeric values, like the population in a certain area (e.g., 4,000).
Quantitative continuous variables can assume any value, including decimals, such as the time taken to complete an exam (e.g., 1:50).

Graphical Representations

A bar graph represents quantitative variables by displaying heights corresponding to class frequency, relative frequency, or percentage.
A pie chart depicts a quantitative variable with slices proportional to class frequency.
A line chart tracks a single quantitative variable measured over time, known as time series data.
A dot plot is the simplest graph for quantitative data, plotting measurements along a horizontal axis.
A stem and leaf plot organizes numerical values where the stem represents the leading digit(s) and the leaves represent the trailing digit(s).

Distribution Shapes

A mound-shaped symmetrical distribution has a mirror image appearance, indicating even distribution.
Skewed right distribution is characterized by the median being greater than the mean, with a few unusually large measurements.
Skewed left distribution shows the peak of data on the right side, with fewer data points on the left.
Bimodal distribution possesses two distinct peaks.

Additional Statistical Tools

A relative frequency histogram is a bar graph for quantitative data that shows how often each class occurs.
Subintervals refer to classes used in data categorization.

Practical Example

For data analysis, consider the ages of 50 tenured faculty at a state university as a case study, emphasizing the application of statistical concepts in real-world scenarios.

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Description

This quiz covers the basics of statistics as introduced in UC Davis STA 13. It includes definitions of key terms like population and sample, providing clear examples for each concept. Perfect for grasping foundational statistical terminology.