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Unformatted text preview: MGMT 2340 Section W01 Business Statistics I Instructor: E. Mark Leany contact via Blackboard online.uen.org alternately: professorleany@gmail.com Sampling Methods and the Central Limit Theorem Chapter 8 257 GOALS 1. Explain why a sample is the only feasible way to learn about a population. 2. Describe methods to select a sample. 3. Define and construct a sampling distribution of the sample mean. 4. Explain the Central Limit Theorem . 5. Use the central limit theorem to find probabilities of selecting possible sample means from a specified population. 257 Why Sample the Population? 1. To contact the whole population would be time consuming . 2. The cost of studying all the items in a population may be prohibitive . CENSUS 3. The physical impossibility of checking all items in the population. 4. The destructive nature of some tests. 5. The sample results are adequate . 258 Probability Sampling z A probability sample is a sample selected such that each item or person in the population being studied has a known likelihood of being included in the sample. z In nonprobability sample inclusion in the sample is based on the judgment of the person selecting the sample. LYING with Statistics z Guy in the Hall of Flags chooses 20 people to ask if they like UVU dances. z Is this a representative sample? z To even it out, a girl assists, she asks 20 guys if they like UVU dances. z Is this a representative sample? Most Commonly Used Probability Sampling Methods z Simple Random Sample z Systematic Random Sampling z Stratified Random Sampling z Cluster Sampling Simple Random Sample EXAMPLE: A population consists of 845 employees of Nitra Industries. A sample of 52 employees is to be selected from that population. The name of each employee is written on a small slip of paper and deposited all of the slips in a box. After they have been thoroughly mixed, the first selection is made by drawing a slip out of the box without looking at it. This process is repeated until the sample of 52 employees is chosen. Simple Random Sample: A sample selected so that each item or person in the population has the same chance of being included. 259 Simple Random Sample: Using Table of Random Numbers A population consists of 845 employees of Nitra Industries. A sample of 52 employees is to be selected from that population....
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This note was uploaded on 12/05/2011 for the course MGMT 2340 taught by Professor Leany during the Winter '11 term at Utah Valley University.
 Winter '11
 Leany

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