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Business Statistics

bbasemester 3
Chapter Wise NotesQuestion BanksSyllabusChapter Wise Questions
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Faculty of Management

2023

Bachelor in Business Administration

Business Statistics

STT 201

Full Marks: 60

Candidates are required to give their answers in their own words as far as practicable. The figures in the margin indicate full marks.

"Section A"

Brief Answer Questions .

[10*1=10]

1.

The covariance of X and Y is 30 and the variances of X and Y are 25 and 64 respectively. Find Karl Pearson's coefficient of correlation between X and Y.

[1]
2.

If the values of upper quartile and lower quartile are 63 and 59 respectively, then calculate the coefficient of quartile deviation.

[1]
3.

The equations of two regression lines are 4X-5Y+33=0 and 20X-9Y-107=0, find the mean values of X and Y.

[1]
4.

Given that P(A∩B) = 0.7, P(A)= 0.4 and P(B) = 0.5,then find out the value of P(A∪B).

[1]
5.

Find P(X=4), the mean of Poisson distribution (λ) is 1.5.

[1]
6.

Calculate the standard error of mean when population size (N) = 1000, sample size (n) =100 and standard deviation (σ) = 10.

[1]
7.

In a moderately asymmetric distribution, the values of mean and mode are 20 and 23 respectively. Compute the value of median.

[1]
8.

Calculate coefficient of variation, when values of mean and standard deviation are 32 and 17 respectively.

[1]
9.

Given that value of correlation coefficient is 0.84, interpret the result on the basis of coefficient of determination.

[1]
10.

List out any four types of random sampling techniques.

[1]

"Section B"

Short Answer Questions (Attempt any FIVE Questions ) .

[5*3=15]

1.

The following table shows the marks distribution of students in a subject:

Marks 0-10 10-20 20-30 30-40 40-50 50-60
Frequency 10 25 45 20 18 12


Find the lowest marks of the top 20% of the students.

[3]
2.

A random sample of 50 items gave mean weight of 7.5 kg and a standard deviation of 1.5 kg. Find 95% confidence limits of weight within which the population mean would lie.

[3]
3.

The following table represents the marks of 100 students.

Marks 0-20 20-40 40-60 60-80 80-100
Students 14 - 27 - 15

Find the missing frequencies when modal marks is 48.

[3]
4.

From the following income distribution of 500 workers in a locality, find the median value of the income distribution.

Income (000 Rs) No. of workers
Below 20 50
20-40 90
40-60 150
60 - 80 100
80 - 100 60
100 & above 50

[3]
5.

From the following income distribution, calculate the appropriate measures of dispersion.

Daily income (Rs) Number of workers
Below 50 10
51-100 18
101-150 25
151-200 20
201-250 16
250 and above 11

[3]
6.

The following information was obtained from two investment companies A and B:

Company A Company B
Average return (000Rs) 28 37
Variance 25 36
No. of observations 100 100



Calculate combined standard deviation.

[3]

"Section C"

Long Answer Questions : (Attempt any THREE Questions ) .

[3*5=15]

1.

The following table shows the average life of electric bulbs manufactured by X and Y companies:

Company X Company Y
No. bulbs n 100 100
Mean life in hours 1300 1250
Standard deviation 80 90


Test whether there is any significant difference in mean life of the electric bulbs produced by two companies at 5% level significance.

[5]
2.

Daily income of the part-time staff of a bank of 50 employees was found to be normally distributed with mean of Rs 1200 and standard deviation of Rs 120. Find the probability of employees having income (a) between Rs 1050 to Rs 1400 (b) between Rs 1250 to Rs 1500.

[5]
3.

From the following distribution, find the coefficient of skewness. Also comment the result.

Monthly income (Rs 000) Number of workers
0-100 15
100-200 50
200-300 75
300-400 40
400-500 30
500- 600 10

[5]
4.

From the following marks distribution of students of a campus, calculate the coefficient of kurtosis. Also, interpret the result.

Marks Below 10 10 - 20 20 - 30 30 - 40 40 - 50 50 & above
No. of students 50 100 150 90 60 50

[5]