# Business Statistics Old Question Paper Year 2018 – Tribhuvan University | BBA

## Business Statistics Old Question Paper Year 2018 | Tribhuvan University | Program BBA

### Group “A”

1. 1) What is sampling? List down the various random sampling techniques.
2. 2) One hundred and twenty Students appeared for a English class test and following are the marks distribution.
 Marks 0-20 20-40 40-60 60-80 80-100 No. of students 10 25 40 30 15

Find the modal marks of the students.

1. 3) A bag contains 3 red, 2 black and 5 white balls. If two balls are drawn at random, what is the probability of getting () both red balls (ii) both white balls.
2. 4) A random sample of 100 patients suffering from a certain disease was given a serum treatment. It was observed that 80% were relieved of the disease. Find 99% confidence limits for the percentage of patients cured.

### Group ‘B’

1. 5) If the average value of Poisson distribution is 2. Find the value of

(i)P(x = 0) (ii) (x<=1) (ii) P(x >= 2)

1. 6) Lives of two models of refrigerators in a recent survey are shown below
 Model A Model B Average life in years 5 6 Standard deviation 3 2

Which model of refrigerators has greater uniformity in life?

1. 7) Following are the income distributions of the 600 employees.
 Income ‘000’ Rs: 0-50 50-100 100-150 150-200 200-250 250-300 No. of employees 40 160 200 100 70 30

Find the lowest income of richest 15% of employees.

1. 8) The following table gives the information of average number of articles produced by Machine A and Machine B respectively with their standard deviations. Test whether the both machines equally efficient on the basis of 50 days of production at 5% level of significance.
 Machine A Machine B Average numbers of articles 200 210 Standard deviation 20 15

### Group ‘C’

1. 9) The following table gives aptitude test scores and productivity indices of 8 randomly selected workers. Find the correlation coefficient aptitude score and productivity index.
 Aptitude score 57 58 59 59 60 61 62 64 Productivity score 67 68 65 68 72 72 69 71

Estimate the productivity index of a worker whose test score is 66.

1. From the following distribution, find skewness and kurtosis. Also comment on the results.
 Marks No. of students 20-30 3 30-40 7 40-50 12 50-60 18 60-70 16 70-80 10 80-90 5 90-100 4