# ISS (Statistical Services) Statistics Paper IV: Questions 75 - 79 of 79

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## Question number: 75

» Design and Analysis of Experiments » Randomized Block and Latin Square Design

Appeared in Year: 2014

### Describe in Detail

Obtain necessary conditions for a symmetric BIBD with an even number of treatments to exist.

### Explanation

Necessary conditions for a symmetric BIBD with an even number of treatments to exist:

The determinant of is given by

=

Since

=

Using the fact

When BIBD is symmetric, r = k and b=

Substituting r = k and b=

## Question number: 76

» Design and Analysis of Experiments » Need for Design of Experiments

Appeared in Year: 2014

### Describe in Detail

What is meant by the design of experiment? Describe the situations in which the three basic designs, namely CRD, RBD and LSD are appropriate, and state the rule or rules by which treatments are allocated to units in these designs.

### Explanation

**Design of experiment: **

Design of experiments may be defined a systematic method to determine the relationship between factors affecting a process and the output of that process.

The design of experiment includes:

(i) Planning of the experiment

(ii) Obtaining the relevant information from it regarding the statistical hypothesis under study

## Question number: 77

» Design and Analysis of Experiments » Split Plot Design and Strip Plot Design

Appeared in Year: 2014

### Describe in Detail

What do you understand by a split-plot design? When will such a design be adopted? Distinguish it from a usual confounded factorial experiment.

### Explanation

**Split-plot Designs: **

The split plot is a design, which involves assigning the levels of one factor to large plots and then assigning the levels of a second factor to subplots within each main plot. Split plot designs have a nested blocking structure i. e. plots are nested within whole plots,

## Question number: 78

» Design and Analysis of Experiments » Randomized Block and Latin Square Design

Appeared in Year: 2014

### Describe in Detail

Define a Latin square design. Show how you split up the total sum of squares into components for this design. Give the analysis of variance table.

### Explanation

** Latin Square Design: **

When the experimental area is divided into rows and columns, and the treatments are allocated such a way that each treatments occurs only once in a row and once in a column, the design is called as Latin square design.

In LSD the number of rows and

## Question number: 79

» Design and Analysis of Experiments » Basic Principle of Experimental Design

Appeared in Year: 2014

### Describe in Detail

Explain clearly the purposes of replications, randomizations and local control in design of experiments.

### Explanation

**Replication: **

Replication means the repetition of the basic experiments. In other words, the repetition of the treatments under investigation is known as Replication. The main purpose of the replication is to average out the influence of the chance factors on different experimental units.

The main advantages of Replication:

(i) It