AP Computer Science Principles: Big Idea 2 — Data and Information

Bit

The smallest unit of data in a computer, representing a binary value of either 0 or 1.

Byte

A group of 8 bits.

Abstraction

Grouping bits together to represent larger, complex data while hiding hardware complexity.

Decimal System

A base 10 number system used by humans, utilizing digits 0-9.

Binary System

A base 2 number system used by computers, consisting of only digits 0 and 1.

Analog Data

Data that is continuous and an infinite stream of values, such as sound or temperature.

Digital Data

Data represented in discrete values, such as MP3 files or JPEG images.

Sampling

The process of measuring an analog signal at regular intervals to convert it into digital data.

Sampling Rate

The frequency at which data is sampled; higher rates yield better quality.

Bit Depth

The number of bits used to represent each sample in digital data, affecting precision.

Overflow Error

An error occurring when a calculation exceeds the maximum storable value.

Round-off Error

Inaccuracy that occurs when binary cannot perfectly represent decimal fractions.

Data Compression

The process of encoding information using fewer bits than the original representation.

Lossless Compression

A method of reducing file size without losing any information.

Lossy Compression

A method of reducing file size by discarding some information, making full restoration impossible.

Metadata

Descriptive data about an object such as the date a photo was taken or its GPS location.

Cleaning Data

The process of correcting or removing corrupt or inaccurate records from a dataset.

Filtering

Retaining only data that meets specific criteria during analysis.

Correlation

A statistical relationship between two variables moving together.

Causation

A relationship where one variable directly causes a change in another variable.

Bias in Data

A distortion in data representation that can affect the outcomes of analysis.

Byte Math

Understanding binary calculations, where 2^10 equals 1024.

Kilo

A metric prefix denoting one thousand (10^3) or approximately 2^10 (1024).

Mega

A metric prefix denoting one million (10^6) or 2^20.

Giga

A metric prefix denoting one billion (10^9) or 2^30.

Tera

A metric prefix denoting one trillion (10^12) or 2^40.