Comp sci data and info

What is lossless data compression?

• It is a form of data compression that reduces the data file size with an acceptable loss of data information. It does not allow the original file to be restored.

• It is a form of data compression that reduces the data file size by removing non-essential data. When the file is restored it appears like the original file.

• It is a form of data compression that is only used for temporary data files. The file is reduced and stays compressed.

• It is a form of data compression that reduces the data file size without any of loss of data information. It allows the original file to be restored.

What is lossy data compression?

• It is a form of data compression that reduces the data file size without any of loss of data information. It allows the original file to be restored.

• It is a form of data compression that reduces the data file size with an acceptable loss of data information. It does not allow the original file to be restored.

• It is a form of data compression that reduces the data file size by removing non-essential data. When the file is restored it appears like the original file.

• It is a form of data compression that is only used for temporary data files. The file is reduced and stays compressed.

How is it possible to reduce data file in size for compression and then restore it to its original format without any loss of information?

• Clever algorithms are used that only remove non-essential "blank" data.

• The removed data is store elsewhere on the Cloud and added later during restoring.

• Repetitive data, like a color on an image, can be stored with a formula.

• It is not really possible to store 100%, but the data loss is not noticeable.

What is metadata?

• It is a name for the data that is lost during data compression.

• It is the data that has been analyzed and classified as significant.

• It is the name for data that is not compressed.

• It is data about data, such as file size, data format, creation date, etc.

Social media companies, like Facebook, lower picture quality of high resolution images before posting them on the Internet. Why is this an acceptable practice?

• Lower quality means smaller files and quicker transmission times.

• Lower quality means smaller files and less memory required for storing the image.

• Most people will not notice any difference. Social media does not require high resolution quality, such as is needed for printing large pictures or zooming.

• All of the above

A high resolution picture is taken of an eagle flying in the sky. Is this picture a good candidate for lossless data compression or should lossy data compression be used?

• Lossy data compression is fine, because the picture started with high resolution.

• This decision cannot be made without knowing the purpose of the image.

• This picture is a good candidate for lossless data compression. Much of the picture will include sky pixels of the same color that can be stored in a formula and restored to its original image quality.

• All still pictures should use lossless data compression. Only audio files and video files can manage lossydata compression well.

The National Security Agency (NSA) collects and processes more data than any other US government agency. The enormous data collection raises concern on a regular basis about privacy issues. What can such an agency do to make US citizens more comfortable about their personal and sensitive information?

• Make assurances that all data, once looked at for terrorist connections, is removed.

• Check only data sources that come from known terrorist individuals and organizations.

• Do not collect or store any data from within the United States.

• Limit initial data collection to metadata until such data triggers security concerns.

Data files start in many different original formats, like numbers, text, still images, videos, and audio sounds. What is true about the storage of all these data files in a computer?

• All data files have a different individual system for storing information. Decimal numbers use base-2 bits. Text uses ASCII values. Images use RGB color triples and audio files convert its analog sound to digital wave length.

• All data files, regardless of its original format, are converted into a digital format and at its lowest level become a sequence of binary bits of ones and zeros that are stored in memory.

• All data files start as analog files that are converted to computer digital, decimal files.

• All of the above

Large data sets are useful in finding patterns in the data that can predict future usage. Which of the following is used to predict future usage?

• Calculating the monthly bill charged

• Using past purchases to recommend products for possible purchase

• Identifying the largest spending addresses

• Identifying the time at which most purchases are made

Suppose that a company is creating an algorithm that matches people to advertisements that they might have an interest in. The company is basing its algorithm on a data source accumulated from data bought from social media. Which of the following sources would be useful for the algorithm?

• Information about a person's video-watching preferences (whether they watch viral videos, reviews, animations, etc.)

• A social network's information on what sites a person likes and follows

• Information on a person's previous purchases

• All of the above