In: Statistics and Probability
1)what could be the different categories of collected
data?
2)Identify the different data storage methods
1) DIFFERENT CATEGORIES OF COLLECTED DATA:
The collected data can be categorised based on two ways:
CATEGORIES BASED ON WHO COLLECTED DATA:
A common classification of data is based upon who collected the data.
(a) PRIMARY DATA:
Data collected by the investigator himself/ herself for a specific purpose. It refers to the data that the investigator collects for the very first time. This type of data has not been collected either by this or any other investigator before. A primary data will provide the investigator with the most reliable first-hand information about the respondents. The investigator would have a clear idea about the terminologies uses, the statistical units employed, the research methodology and the size of the sample. Primary data may either be internal or external to the organization.
Example: Data collected by a student for his/her thesis or research project.
(b) SECONDARY DATA:
Data collected by someone else for some other purpose (but being utilized by the investigator for another purpose). It refers to the data that the investigator collects from another source. Past investigators or agents collect data required for their study. The investigator is the first researcher or statistician to collect this data. Moreover, the investigator does not have a clear idea about the intricacies of the data. There may be ambiguity in terms of the sample size and sample technique. There may also be unreliability with respect to the accuracy of the data.
Example: Census data being used to analyse the impact of education on career choice and earning.
CATEGORIES BASED ON NATURE OF DATA:
QUANTITATIVE DATA:
Example: An evaluator may wish to measure the knowledge of social skills amongst program participants. He/she may administer surveys to participants to test their knowledge of these social skills.
QUALITATIVE DATA:
Example: Evaluators may wish to look at the level of engagement of afterschool staff in program trainings. He/she might conduct interviews of these staff members to capture the level of engagement that each staff member feels they have during the trainings.
MIXED METHODS DATA:
Example: You may administer a survey to participants which solicits answers that are eligible for statistical analysis as well as conduct a focus group with a sampling of participants to capture any nuances the survey may have missed.
2) DIFFERENT DATA STORAGE METHODS:
The main methods of data storage are:
Hard disks:
Often called a disk drive, hard drive or hard disk drive, this method of data storage stores and provides relatively quick access to large amounts of data. The information is stored on electromagnetically charged surfaces called 'platters'.
Floppy disks:
A floppy disk is a type of magnetic disk memory which consists of a flexible disk with a magnetic coating. Almost all floppy disks for personal computers now have a capacity of 1.44 megabytes. Floppy disks are readily portable, and are very popular for transferring software from one PC to another. They are, however, very slow compared to hard disks and lack storage capacity. Increasingly, therefore, computer manufacturers are not including floppy disk drives in the products as a built-in storage option.
Tape storage:
Tape is used as an external storage medium. It consists of a loop of flexible celluloid-like material that can store data in the form of electromagnetic charges. A tape drive is the device that positions, writes from, and reads to the tape. A tape cartridge is a protectively-encased tape that is portable.
Optical disks:
An optical disc is a storage medium that can be written to and read using a low-powered laser beam. A laser reads these dots, and the data is converted to an electrical signal, finally converted into the original data.
CD-R :
Compact Disc-Recordable ("CD-R") discs have become a universal data storage medium worldwide. CD-Rs are becoming increasingly popular for music recording and for file storage or transfer between personal computers. CDR discs are write-once media. This means that - once used -they cannot be erased or re-recorded upon. CD-R discs can be played back in any audio CD player or CD-ROM drive, as well as many DVD players and drives.
CD-RW:
Compact Disc-Rewritable (CD-RW) disks are rewritable and can be erased and re-recorded upon over and over again. CD-RW discs can only be used on CD players, CD-ROM drives, and DVD players and drives that are CD-RW playback-compatible.
DVD:
A DVD (Digital Versatile Disc or Digital Video Disc) is a high density optical disc with large capacity for storage of data, pictures and sound. The capacity is 4.7 GB for single sided, singe layer DVD disc - which is approximately 7 times larger than that of a compact disc.