Mr6 pt10


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Mr6 pt10

  1. 1. Business Research Sampling Technique Lecture 6 Hamendra Dangi [email_address] 9968316938
  2. 2. Define the Target Population <ul><li>The target population is the collection of elements or objects that possess the information sought by the researcher and about which inferences are to be made. The target population should be defined in terms of elements, sampling units, extent, and time. </li></ul><ul><ul><li>An element is the object about which or from which the information is desired, e.g., the respondent. </li></ul></ul><ul><ul><li>A sampling unit is an element, or a unit containing the element, that is available for selection at some stage of the sampling process. </li></ul></ul><ul><ul><li>Extent refers to the geographical boundaries. </li></ul></ul><ul><ul><li>Time is the time period under consideration. </li></ul></ul>
  3. 3. Classification of Sampling Techniques Sampling Techniques Nonprobability Sampling Techniques Probability Sampling Techniques Convenience Sampling Judgmental Sampling Quota Sampling Snowball Sampling Systematic Sampling Stratified Sampling Cluster Sampling Other Sampling Techniques Simple Random Sampling
  4. 4. Question for Discussion <ul><li>A manufacture would like to survey user to determine the demand potential for a new power press. The new press has a Capacity of 500 tons and Cost Rs 2, is used for forming products from light weight and heavy weight steel and can be used in automobile , Construction equipment and major appliances manufactures </li></ul>
  5. 5. <ul><li>A) Identify the Sampling frame and Population that could be used. </li></ul><ul><li>B) Describe how Simple Random Sampling can be used </li></ul><ul><li>C) Could a stratified sampling can be used if so how ? </li></ul><ul><li>D) which sampling technique would you recommend and why? </li></ul>
  6. 6. Definitions and Symbols <ul><li>Parameter : A parameter is a summary description of a fixed characteristic or measure of the target population. A parameter denotes the true value which would be obtained if a census rather than a sample was undertaken. </li></ul><ul><li>Statistic : A statistic is a summary description of a characteristic or measure of the sample. The sample statistic is used as an estimate of the population parameter. </li></ul>
  7. 7. Definitions and Symbols <ul><li>Precision level : When estimating a population parameter by using a sample statistic, the precision level is the desired size of the estimating interval. This is the maximum permissible difference between the sample statistic and the population parameter. </li></ul><ul><li>Confidence interval : The confidence interval is the range into which the true population parameter will fall, assuming a given level of confidence. </li></ul><ul><li>Confidence level : The confidence level is the probability that a confidence interval will include the population parameter. </li></ul>
  8. 8. Symbols for Population and Sample Variables _ _ _ _ _
  9. 9. Example <ul><li>The mean length of a certain cutting tool is 41.5 hours with a S.D of 2.5 hours ,What is the probability that a SRS of Size 50 drawn from this population will have a between 40.5 hours and 42 hours </li></ul><ul><li>( Z= 2.821 Area = 0.4997 , 1.4140 A= 0.4207) </li></ul>
  10. 10. <ul><li>SE = 2.5/SQRT(50)= 0.3536 </li></ul><ul><li>40.5-41.5/.3536= 2.8281 </li></ul><ul><li>42-41.5/0.3536= 1.4140 </li></ul>
  11. 11. Example <ul><li>CEO of a life Insurance company wants to undertake a survey of the huge number of insurance policies that the company has underwritten. The company makes a yearly profit on each policy that is distributed with mean Rs 8000 and SD of Rs 3000 .It is desirable that survey must be large to reduce SE not more than 1.5 % of Population Mean ,Determine the sample size </li></ul>
  12. 12. Example <ul><li>A continuous manufacturing process produces items whose weights are normally distributed with a mean weight of 800 gms and a SD of 300 gms , A random sample 16 item is to be drawn from the process </li></ul><ul><li>Construct 95% confidence limit </li></ul>
  13. 13. <ul><li>Population Mean +/_ 1.96 SE </li></ul>
  14. 14. Sample Size Determination for Means and Proportions Table 12.2 _ -
  15. 15. Question for Discussion <ul><li>To determine the effectiveness of the adervertising campaign for a new DVD player ,management would like to know what percentage of the household are aware of the new brand .The advertising agency think this figure is as high as 70% .The management would like a 95% confidence interval and margin of error not greater than plus or minus 2% </li></ul><ul><li>What Sample Size should used </li></ul><ul><li>Suppose managements wanted to be 99% Confidence with +-3% error .How would the sample Size change </li></ul>
  16. 16. Question for Discussion <ul><li>If we don’t know sample size than how can we choose value of Standard deviation ? </li></ul>
  17. 17. Discussion on Minor Test and Mid Term Review
  18. 18. Class Activity <ul><li>You work in the marketing research department of Mc Donald's .Mc D has developed new cooking process that makes the burgers taste better. However before new burger is introduced in the market ,taste test will be conducted. How should the sample size for these taste test be determined ?What approach would you recommend ? Justify your recommendation to a group of students representing Mc Donald's Management </li></ul>