Basic Statistics for Economics — DU B.A. (Hons.) Economics Previous Year Question Papers

1. (a) Define the ‘Mean’, ‘Median’, and ‘Mode’. Which measure is the best measure of central tendency? (10) (b) A set of 5 sample observations has a mean of 20 and a standard deviation of 4. If each observation is multiplied by 3, what will be the new mean and the new standard deviation? (5) 2. The following data shows salary in INR of sample of 15 middle level managers (a) Compute the median salary. (b) Compute the mean annual salary and discuss why it differs from the median. (c) Compute the first and third quartiles. (5+5+5) 3. Answer the following : (a) Compute the probability of randomly drawing five cards from a deck of 52 cards and getting exactly one ace. (b) Five boys and Five girls have to be seated in a row. Find the probability that two particular girls are never together. (5+5) 4. The following data is on the work related fatalities : Causes of fatality Number of fatalities Transportation incidents 1795 Assaults and violent acts 837 Contact with equipment 741 Exposure to harmful substances 404 If a fatality is chosen at random (a) What is the probability it resulted from a fall? (b) What is the probability that fatality occurred from a reason other than fire? (5+5) 5. If P(A1) = 0.20 AND P(A2) = 0.50 AND P(A3) = 0.30. The conditional probabilities P(B/A1) = 0.50, P(B/A2) = 0.40, P(B/A3) = 0.30 Section – III 6. For the following data (b) Find Var (y). (c) Find Coefficient of variation. (2.5+2.5+5) 7. In a university, 20% of the students withdraw without completing a course, assuming 20 students registered for the course (a) Compute the probability that 2 or fewer students will withdraw (b) Compute the probability that exactly 4 will withdraw (c) Compute the expected number of withdrawals (2.5+2.5+5) 8. (a) Explain the characteristics of a normal distribution (b) Assuming the test scores to be normal distributed with a mean of 450 and a standard deviation of 100, what percentage of people taking the test score between 400 and 500. (5+5) 9. (a) (b) Explain the different kinds of random and non- random sampling methods. What is Type I and Type II error? (5+5) 10. The following data is from a normal distribution : (a) What is the point estimate of the population mean? (b) With 95% confidence, what is the margin of error for the estimation of population mean? (c) What is the 95% confidence interval for the population mean? 11. Annual income of a person in state A was $838 per person. A sample of 60 individuals showed a per person annual income of $745 in the other state B. If standard deviation of population was $300. Formulate the hypothesis for a test to determine whether the sample data. Support the conclusion that the population annual income is lower in state A than in state (a) What is the p value? (b) At a = 0.01, what is your conclusion? (5+5) pe tae fe tep p (4) Lade ye Fie Hod ye parke if late belte fa (se) Cumulative Probability