Solve your IGNOU Doubts

Question:

A company has the procurement pattern of five items irrespective of their level of demand as given in the table 1:

Item No.	Annual Demand (Rs.)	No. of orders per year	Order Size (Rs.)
1	10,00,000	4	2,50,000
2	6,40,000	4	1,60,000
3 4	9,00,000 2,500	4 4	22,500 625
	9,00,000 2,500	4 4	22,500 625
5	1,600	4	400

Reduce the inventory levels while keeping total number of orders per year the same.

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Question:

What are advantages and limitations of using this classification method ?

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Question:

Discuss the ABC classification inventory using a suitable diagram.

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Question:

A television manufacturer requires 24000 pieces of wire (each 2 cm long) every month for assembly. Ordering cost per order is Rs. 2000 and carrying (or holding) cost is 25 percent of the unit price. The price per unit of a piece is Rs. 5. Assuming delivery is instantaneous, find the economic order quantity (EOQ) and the reorder point.

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Question:

Discuss the fixed quantity order model of inventory control system with a suitable diagram.

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Question:

What do you understand by Economic Order Quantity (EOQ) ? Explain EOQ using suitable diagram.

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Question:

Describe various costs related to inventory.

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Question:

Describe various types of inventory used in manufacturing setup.

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Question:

What are objectives of inventory management ?

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Question:

Why do organizations need inventory ?

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Question:

Create following two matrices A and B with following elements.

A= $\binom{1,2}{0,1}$ ,B= $\binom{-3,1}{2,-1}$

Write R commands to do the following tasks:
(i) Multiply the two matrices.
(ii) Combine the two matrices row-wise.
(iii) Create a function that computes the following expression:

A ²+3*B

X	Y	Z	W
0.04	0.16	0.53	A
0.82	0.87	0.84	A
0.32	0.65	0.99	A
0.39	0.83	0.42	A
0.31	0.93	0.78	A
0.83	0.31	0.41	A
0.73	0.74	0.88	A
0.32	0.39	0.50	B
0.60	0.85	0.68	B
0.65	0.28	0.86	B
0.55	0.95	0.77	B
0.53	0.35	0.32	B
0.91	0.01	0.91	B
0.84	0.61	0.37	B

Write R commands to:
(i) Compute the group wise means of x, y and z according to the groups
defined by w column using apply family function.
(ii) Sort RData according the y column of it.

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Question:

Write R commands to:
(a) Create a function to compute ranks (in case of tied ranks) of the given data.
(b) Create a date object named Ddata consisting of the following dates.
26Jan2023, 15Aug2023, 02Oct2023, 05Sep2023
(c) Create an array of two dimension with following elements.

$\frac{\left ( 2 4 /01\right )}{92}$

Also, extract the row shown in the rectangular box.
(d) Create the graph of the following function.
f(x) x , -5 x 5

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Question:

The following data relates to the number of items produced per shift by two workers for a number of days.

Worker A	19	22	24	27	24	18
Worker B	26	37	40	35	NA	NA

(a) Write R command to create a list named LT with worker’s data. Also, after creating
the list, do the following tasks:
(i) Use a suitable loop function to compute the mean of number of items
produced by each worker in a single line command.
(ii) Extract the worker A data from it by using two different approaches.
(b) Write R command to create a data frame named DF with worker’s data and do the
following tasks:
(i) Use suitable function to remove NA from the data and then create a scatter
plot.
(ii) Write the known data obtained in step (i) to a .txt file named “WORK”.

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Question:

Check whether the given loop is finite or infinite. If infinite, do the necessary changes in the written loop to make it finite.

x<-0
repeat{
print(x^2)
x<-x+1
if(x<5) print(x) }

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Question:

Write R commands to create a bar plot of the following data by using arguments of
the used function for filling up the bars and to give labels to the axis:
5, 10, 8, 7, 8, 5, 8, 7, 5, 8, 9, 6, 8, 8, 8

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Question:

Differentiate between the use of the sep and collapse arguments of the paste() function.

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Question:

Attempt the following:

(a) Write the output of the following statements:

(i) rep(x=c(T,F,T,F), times=c(2,1,2,3))
(ii) 5%/%3; diag(3)

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Question:

The marketing manager of a company recorded the number of mobiles sold quarterly for which are given in the following table:

Quarter	Q1	Q2	Q3	Q4
2018	48	41	60	65
2019	58	52	68	74
2020	60	56	75	78

(i) Find the quarterly seasonal indexes for the mobile sold using the ratio to trend
method.
(ii) Do seasonal forces significantly influence the sale of mobile? Comment.
(iii) Also find the deseasonalised values.

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Question:

Consider the time series model

$y_{1}=10+0.5y_{t-1}-0.8y_{t-2}+\varepsilon _{1}$

Where $\varepsilon _{1}-N\left [ 0,1 \right ]$
(i) Is this a stationary time series?
(ii) What are the mean and variance of the time series?
(iii) Calculate the autocorrelation function.
(iv) Plot the correlogram.

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Question:

At a call centre, callers have to wait till an operator is ready to take their call. To monitor this process, 5 calls were recorded every hour for the 8-hour working day. The data below shows the waiting time in seconds:

Time

Sample Number

9 a.m
10
11
12
1 p.m.
2
3
4

7
11
12
11
7
10
8

9
10
12
8
10
7
7
11

15
7
10
6
6
10
4
11

4
6
9
9
14
4
10
11

11
8
10
12
11
11
10
7

(i) Use the data to construct control charts for mean and comments about the
process. If process is out of control, then calculate the revised control limits.
(ii) Construct the CUSUM chart when the process is under control and draw the
conclusion about the process.
(iii) If the specification limits as the 8±2, then calculate the process capability index
Cpk and impetrate the result.
(iv) Also find the percentage of calls lie outside the specification limits assuming
that calls follow the normal distribution.

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