ICS Part 2 Online Preparation for Statistics Short questions Chapter Wise

What stands for Z in normal distribution ?

• Ans 1: Z is a standardized normal variate (SNV) having zero mean and unit variance.

What is random sampling ?

• Ans 1: it is the process of selecting a part or some elements from the population using probability theory.

Do you think computers are becoming easier to use ? Why or why not ?

• Ans 1: Yes, it is now very easy to use a computer due to following reasons:Firstly, due to development of application soft wares of every field. They are easily available in the market for common user. There are ready made programs and there is no need to Write instructions and remember commands. You can easily operate a computer and get you results by just clicking a few icons.Secondly, the computer prices become very low and now it is affordable for a common person.

• Ans 1:

What are the two main components of a CPU ? Explain what each one does ?

• Ans 1: The CPU contains two basic parts, the CU (Control Unit) and ALU (Arithmetic Logic Unit).All the components / actions of a computer are controlled from the control unit. Control unit schedules the input/output operations when computer runs a programme, CU executes the instructions in order.On the other hand ALU performs arithmetic and logical operations (decision making) according to the instruction.

What is meant by sampling distribution of means ?

• Ans 1:

As the ranks are always positive therefore, it can be conclude that rank's correlation coefficient will always be positive.

• Ans 1: No, its value always lies in between -1 and +1.

• Ans 1:

Why correction for continuity is in above transformation

• Ans 1: To make discrete Binomial variable X as continuous Normal variable.

What are two main differences of Correlation and Regression ?

• Ans 1: Regression is a relationship of dependency whereas correlation represents the independence of variables upon each other; the result of a regression problem is an approximating equation which can be used for further prediction whereas the final result of a correlation technique is a number indicating the nature and strength of relationship and which cannot be used for prediction purposes.

• Ans 1:

Define type of computer.

Digital computer

Analogue computer

Hybrid computers

• Ans 1: Digital Computer: Digigal computer proces data in numerical form using digigal circuits.They perfom arithemetic and logic operations with discrete values. These values are 0 and 1.
• Ans 2: Analogue Computer: The analog computers accept input and give output in the form of analog singals. The output is measured on a scale.These computers use electronic and mechanical phenomena to solve a problem by convering one kind of physical quantity into another the analogue computer have very high speed computing elements used to process physical quantities.
• Ans 3: Hybrid Computer: Hybrid computers are teh combination of analoue and digital computers. These computers contain both digital and analouge components. In Hybrid computers, the users can process data. These are special purpose computer. These computers are used in robotices and medical labs.

What is sampling error ? How can we reduce this error ?

• Ans 1: It is the difference between a statistic and respective parameter. It can be reduced by employing better technique, supervision, randomness and increasing the sample size.

What are the mean and standard deviation of a Standardized normal Variate Z ?

• Ans 1: E (Z) = 0 and S.D (Z) = 1

What is stratified sampling ?

• Ans 1: It is a sampling scheme in which proportionate number of sampling elements are randomly selected from different strata's or groups of a heterogeneous population.

What is meant by linear regression ?

• Ans 1: A statistical method providing best possible linear relationship between a dependent variable and an independent variable.

What is systematic sampling ?

• Ans 1: it is a sampling scheme in which every k^th element is selected from an arranged population with a random start from the first k elements. Where
  k = N/n

What do we mean by nature of the relationship ?

• Ans 1: By nature of the relationship we mean that whether the relationship is linear or curvilinear; positive or negative etc.

• Ans 1:

What does interval estimator (or confidence interval) mean ?

• Ans 1: It is a random interval of the sample data that is expected to include the unknown parameter it its range with a certain degree of confidence.