UGC Net Computer Science Paper II Dec 13 Page 2

UGC Net Computer Science Paper II Dec 13 Page 2 Solved

11. The student marks should not be greater than 100. This is

(A) Integrity constraint

(B) Referential constraint

(C) Over-defined constraint

(D) Feasible constraint

Answer A

Explanation :-

Before one can start to implement the database tables, one must define the integrity constraints. Intergrity means something like 'be right' and consistent. The data in a database must be right and in good condition.

There are the domain integrity, the entity integrity, the referential integrity and the foreign key integrity constraints.

Domain Integrity

Domain integrity means the definition of a valid set of values for an attribute. You define 

data type, 

• lenght or size
• is null value allowed
• is the value unique or not
• for an attribute.

UGC Net Computer Science Paper II Dec 13 Page 1

UGC Net Computer Science Paper II Dec 13 Page 1

1. When data and acknowledgement are sent in the same frame, this is called as

(A) Piggy packing

(B) Piggy backing

(C) Back packing

(D) Good packing

Answer B

Explanation :-

he usual purpose of piggybacking is simply to gain free network access rather than any malicious intent, but it can slow down data transfer for legitimate users of the network. Furthermore, a network that is vulnerable to piggybacking for network access is equally vulnerable when the purpose is data theft, dissemination of viruses, or some other illicit activity.


It's quite simple to access an unsecured wireless network: All you have to do is get into the range of a Wi-Fi hotspot's signal and select your chosen network from the options presented. However, unauthorized network access, even to free Wi-Fi, may be illegal. People have been fined for accessing hot spots from outside businesses, such as coffee shops, that provide free Wi-Fi for customers' use. (http://whatis.techtarget.com/)

2. Encryption and Decryption is

UGC Net Computer Science First Paper December-13 Page-1

UGC Net Computer Science First Paper December-13 Page-1

1. Which is the main objective of research ?

(A) To review the literature

(B) To summarize what is already known

(C) To get an academic degree

(D) To discover new facts or to make fresh interpretation of known facts

Answer D

UGC Net Computer Science Paper 1 December 12 , Page 6 Solved

UGC Net Computer Science Paper 1 December 12 , Page 6 Solved

51. Which of the following sampling methods is based on probability ?

(A) Convenience sampling

(B) Quota sampling

(C) Judgement sampling

(D) Stratified sampling

Answer D

Explanation :-

Convenience Sample 

A convenience sample is one of the main types of non-probability sampling methods. A convenience sample is made up of people who are easy to reach.

Consider the following example. A Company interviews shoppers at a local mall. If the mall was chosen because it was a convenient site from which to solicit survey participants and/or because it was close to the Company 's home or business, this would be a convenience sample.

Quota Sampling

A sampling method of gathering representative data from a group. As opposed to random sampling, quota sampling requires that representative individuals are chosen out of a specific subgroup. For example, a researcher might ask for a sample of 100 females, or 100 individuals between the ages of 20-30.

Judgment Sample 

Judgment sample is a type of nonrandom sample that is selected based on the opinion of an expert. Results obtained from a judgment sample are subject to some degree of bias, due to the frame and population not being identical. The frame is a list of all the units, items, people, etc., that define the population to be studied.

For example, when interviewing manufacturers in the pharmaceutical industry to determine their preferred brand of equipment, the schedules, availability and willingness of the possible subjects are taken into account. Rather than performing random sampling and selecting subjects who are unavailable, an expert employs judgment sampling and selects units whose availability and attitude are compatible with the study.

Stratified Sampling

Stratified sampling refers to a type of sampling method . With stratified sampling, the researcher divides the population into separate groups, called strata. Then, a probability sample (often a simple random sample ) is drawn from each group.

Stratified sampling has several advantages over simple random sampling. For example, using stratified sampling, it may be possible to reduce the sample size required to achieve a given precision. Or it may be possible to increase the precision with the same sample size.