LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034
B.Sc. DEGREE EXAMINATION – STATISTICS
FIRST SEMESTER – APRIL 2008
ST 1500 – STATISTICAL METHODS
Date : 03/05/2008 Dept. No. Max. : 100 Marks
Time : 9:00 – 12:00
PART – A
(10 x 2 = 20 marks)
Answer ALL the questions.
- Distinguish between Census and sample.
- State the objectives of classification of data.
- Why do we call Arithmetic mean is a good average?
- When do you say a distribution is skewed? Sketch positive and negative skew ness.
- What is curve fitting?
- Write down the normal equations for fitting .
- If for two variable X and Y, correlation coefficient
find the regression co efficient of X onY.
- If two regression lines are and for two variables X and Y, find the mean values of X and Y.
- In a report on consumers preference, it was given that out of 500 persons surveyed 410 preferred variety A, 380 preferred variety B and 270 persons liked both. Are the data consistent?
- State any two characteristics of Yule’s coefficient of Association.
PART – B
(5 x 8 = 40 marks)
Answer any 5 questions.
- Draw ogive curves for the data given below:
|No. of Shops||3||6||10||15||8||4||2|
- Distinguish between Classification and Tabulation.
- Calculate Karl Pearson’s Co efficient of Skewness for the data given below. On the basis of mean, median and standard deviation.
- Bring out the relationship between to the following data:
- Fit a parabola of second degree to the following data
- What do you understand by regression? Why there are two regression equations? What are its uses?
- From the following data, calculate the coefficient of rank correlation between X and Y
- 1660 candidates appeared for a competitive examination. 422 were successful, 256 had attended a coaching class, and of these 150 came out successful. Estimate the utility of the coaching classes.
PART – C
(2 x 20 = 40 marks)
Answer any TWO questions.
- a) Calculate mean deviation from median from the following data.
- b) From the prices of shares X and Y given below, state which share is more stable in value
- It is known that the readings for x and y given below should follow a law of the form , where a and b are constants
use the method of least squares to find the best values of a and b.
- Calculate and from the data given below
|No. of Students:||8||12||20||30||15||10||5|
- Calculate the two regression equations Y on X and X on Y and correlation coefficient .
Also estimate the likely demand when the price is Rs.20.
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