ap comp sci test 2

What is a bit?

A bit (binary digit) is the smallest unit of digital data. It can be either 0 or 1.

How many bits are in a byte?

8 bits.

How do computers represent data?

Computers represent data digitally using bits (0s and 1s).

What is abstraction?

Simplifying something by focusing on the important information and leaving out unnecessary details.

What can groups of bits represent?

Numbers, characters, colors, and other types of data.

Can the same sequence of bits represent different things?

Yes. The meaning depends on how the bits are interpreted.

What is analog data?

Data that changes smoothly over time rather than in separate steps.

Give three examples of analog data.

Sound pitch or volume, colors in a painting, and a runner's position during a race.

What is digital data?

Data represented using separate values, such as combinations of 0s and 1s.

How can data values be stored in programs?

In variables, lists, or standalone constants

What are bits grouped together used to represent?

Abstractions such as numbers, characters, and colors

Can the same bit sequence represent different data?

Yes. Its meaning depends on the context

Give three examples of analog data.

Sound pitch, music volume, and a sprinter's position

What is sampling?

Measuring an analog signal at regular intervals.

How does sampling help computers represent analog data?

It takes measurements that can be stored digitally as bits.

What determines the bits needed to store a sample?

The number of bits required to represent its measured value

What is integer overflow?

When a calculation produces a value outside the representable range

Why can fixed-size integers cause errors?

They have a limited range of representable values

What limits integer size in some programming languages?

The available computer memory

What happens when real numbers use a fixed number of bits?

Their range and precision are limited.

What is a round-off error?

A difference caused by storing or calculating an approximate number.

Why are some real numbers approximations in computers?

Some values cannot be represented exactly with the available bits.

What is the binary number system?

Base 2; it uses only the digits 0 and 1.

What is the decimal number system?

Base 10; it uses the digits 0 through 9.

What determines a digit's value in a number?

Its digit and its place value.

What are binary place values, from right to left?

Powers of 2: 1, 2, 4, 8, 16, 32, and so on.

How do you convert binary to decimal?

Add the place values of every position containing a 1.

How do you compare binary numbers?

Convert them to decimal or compare their place values.

What is data compression?

Reducing the number of bits needed to store or transmit data.

Does using fewer bits always mean less information?

No. Fewer bits do not necessarily mean less information.

What affects how much compression is possible?

The original data's redundancy and the algorithm used.

What is lossless compression?

Compression that allows the original data to be reconstructed completely.

What is lossy compression?

Compression that reconstructs only an approximation of the original data

When should lossless or lossy compression be used?

Lossless when exact recovery matters; lossy when smaller files or faster transmission matter more.