Gauhati University
B.Com Examination
Business Statistics 2013
Full Marks: 80
Pass Marks: 24
Time: 3 Hours
1. (Answer Nos. 1, 2, and 3, and any four from the rest)
a) State whether the profit margins of a company during the last eight years constitute statistical data or not. (1)
b) Fill in the blank: Data collected for the first time are called ________. (1)
c) Which of the following relations is not true? (1)
1) Q₂ = Median
2) P₅₀ = Median
3) D₅ = Median
4) D₅₀ = Median
d) What is the relationship between the standard deviation of the following two series? (1)
Series 1: 10, 20, 30, 40, 50, 80, 120
Series 2: 1, 2, 3, 4, 5, 8, 12
e) Select the correct answer: If the correlation between x and y is negative, then the regression coefficient of x on y is (1)
a) Positive
b) Negative
c) Not certain
f) Fill in the blank: The independent variable values in interpolation and extrapolation are termed as ________. (1)
g) Fill in the blank: Cost of living index numbers are also known as ________. (1)
h) Select the correct answer: The component of time series associated with the sale of wool and umbrella is (1)
a) Secular trend
b) Irregular variations
2.a) Mention two situations in which census survey is a must. (2)
b) What do you mean by Kurtosis? (2)
c) Find E(X) for the following probability distribution of X: (2)
d) What is type I error? (2)
e) Mention two properties of correlation coefficient. (2)
3. (Answer any four parts)
a) Write a note on the limitations of statistics. (5×4=20)
b) Explain briefly the use of diagrams in presenting statistical data.
c) Determine mode for the following distribution:
d) What is Skewness? Explain the different types of Skewness.
e) If A, B, and C are mutually exclusive and exhaustive events, and P(A) = 1/2 P(B) and P(B) = 2/3 P(C), find P(A), P(B), and P(C).
f) What is a control chart? Explain the reason for 3σ control limits for a control chart.
4.a) Calculate mean and standard deviation for the following distribution: (3+4=7)
b) Differentiate between primary and secondary data. (3)
5.a) What do you mean by correlation between two variables? Mention the different types of correlation. (2+2=4)
b) The following data are about sales and advertisement expenditure of a firm:
Estimate the likely sales for the proposed advertisement expenditure of Rs. 10 crores. (3)
What would be the advertisement expenditure if the firm fixes a sales target of 60 crores of rupees? (3)
6. Write a brief note on the usefulness of index numbers. (4)
7.a) What is a binomial probability distribution? Mention the properties of this distribution. (2+4=6)
b) If 5% of electric bulbs manufactured by a company are defective, find the probability that in a sample of 100 bulbs:
1) None is defective
2) 5 bulbs are defective
(Given: e⁻⁵ = 0.007)
8.a) What is index number? Write down the formulae of Laspeyre’s, Paache’s, and Fisher’s index numbers. (1+3=4)
b) Write short notes on: (3×2=6)
1) Level of significance
2) Usefulness of interpolation in Commerce
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