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ASK THE PROFESSOR FORUM

Course Documents

Chapter 1 - Intro

Chapter 2 - Methods for Describing Sets of Data

Chapter 3 - Probability

Chapter 4 - Discrete Random Variables

Chapter 5 - Normal Random Variables

Chapter 6 - Sampling Distributions

Chapter 7 - Confidence Intervals

Chapter 8 - Tests of Hypothesis: One Sample

Chapter 9 - Confidence Intervals and Hypothesis Tests: Two Samples

Sample Exam I: Chapters 1 & 2

Sample Exam II: Chapters 3 & 4

Sample Exam III: Chapters 5 & 6

Sample Exam IV: Chapters 7 & 8

Ask the Professor Forum

Hey Professor,

Im reviewing the lecture questions. For number 94 on chapter 6, how did they figure out the variance and show that sample mean was an unbiased estimator of the mean (part B and C of question 94). It gave the answer but did not explain.

Posted to STATS 1 on Thursday, November 7, 2013   Replies: 1


Professor Mcguckian
11/08/2013
12:15 AM EST

Hi Kimberly,

To get the mean and standard deviation of this discrete probability distribution, you use the formulas provided in chapter four. To show the sample mean is unbiased, you must show that the expected value for X-bar is equal to the population mean. The hint in part c explains what needs to be shown, so there isn't much more to say about the theory involved.

However, the details can be confusing, so I understand why you are asking about this problem. If you are a student in my class, you do not need to know this problem. If you did need to know it, it would be covered in a video. For most people, seeing this example worked out is just not very useful for furthering their understanding of the topic.  They typically get lost in the details and are unable to see the big picture. If you can do the exercises from this section, you know what you need to know about this problem.

Let me know if you are taking another professor and need me to go over the details of the work to solve this problem.

Professor McGuckian

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