QUESTION 1

(a) The salaries of employees of a firm are found to be follow a normal distribution of mean Rs 13 500 and standard deviation of Rs 3000.

(i) Calculate the probability that an employee chosen randomly gets a salary 1. less than or equal to Rs 15000. 2. greater than Rs12000. 3. between Rs 12500 and Rs 14000.

(ii) 25% of the employees will have salaries less than which amount?

(b) Oil is automatically filled in jars by a machine in the production line of a factory. In a sample of 100 jars, the mean weight is found to be 505 g and the standard deviation is of 9 g

(i) Determine the 95 % confidence interval for the mean weight of the jars

(ii) Interpret your result in (i)

QUESTION 2

(a) Analyse the different methods for collecting data

(b) Explain by taking examples 3 types of Sampling techniques.

(c) Discuss the advantages and disadvantages of a written questionnaire