ผลต่างระหว่างรุ่นของ "Probstat/homework 2"

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== Part 2: Distribution of sample means. ==
 
== Part 2: Distribution of sample means. ==
  
2.1 Suppose that the population is normally distributed with mean <math>\mu=10</math> and variance <math>\sigma^2 = 4</math>.  Let <math>\bar{X}</math> be the mean of  a sample of size 10. Describe the distribution of <math>\bar{X}</math>.
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2.1 Consider a discrete random variable <math>Y</math> where <math>P\{Y=0\} = 0.3</math>, <math>P\{Y=1\} = 0.3</math>, and <math>P\{Y=2\} = 0.4</math>.
  
2.2 Find <math>P\{\bar{X} > 11\}</math>. (Hint: use the standard normal table to find the answer.)
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(a) If we take a sample of size 2, and let <math>\bar{Y}</math> be the sample mean.  Describe the distribution of <math>\bar{Y}</math>.
  
2.3 Find <math>P\{|\bar{X} - 10 | > 1\}</math>. (Hint: use the standard normal table to find the answer.)
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(b) If we take a sample of size 3, and let <math>\bar{Y}</math> be the sample mean.  Describe the distribution of <math>\bar{Y}</math>.
  
2.4 Consider a discrete random variable <math>Y</math> where <math>P\{Y=0\} = 0.3</math>, <math>P\{Y=1\} = 0.3</math>, and <math>P\{Y=2\} = 0.4</math>.
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2.2 Suppose that the population is normally distributed with mean <math>\mu=10</math> and variance <math>\sigma^2 = 4</math>.  Let <math>\bar{X}</math> be the mean of  a sample of size 10. Describe the distribution of <math>\bar{X}</math>.
  
(a) If we take a sample of size 2, and let <math>\bar{Y}</math> be the sample meanDescribe the distribution of <math>\bar{Y}</math>.
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2.3 Find <math>P\{\bar{X} > 11\}</math>.  (Hint: use the standard normal table to find the answer.)
  
(b) If we take a sample of size 3, and let <math>\bar{Y}</math> be the sample meanDescribe the distribution of <math>\bar{Y}</math>.
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2.4 Find <math>P\{|\bar{X} - 10 | > 1\}</math>.  (Hint: use the standard normal table to find the answer.)
  
 
== Part 3: Estimations and confidence intervals. ==
 
== Part 3: Estimations and confidence intervals. ==

รุ่นแก้ไขเมื่อ 15:43, 29 พฤศจิกายน 2557

This is part of [probstat]].

Deadline: December 7th, 2014.

Part 1: Review of the normal distributions.

Part 2: Distribution of sample means.

2.1 Consider a discrete random variable where , , and .

(a) If we take a sample of size 2, and let be the sample mean. Describe the distribution of .

(b) If we take a sample of size 3, and let be the sample mean. Describe the distribution of .

2.2 Suppose that the population is normally distributed with mean and variance . Let be the mean of a sample of size 10. Describe the distribution of .

2.3 Find . (Hint: use the standard normal table to find the answer.)

2.4 Find . (Hint: use the standard normal table to find the answer.)

Part 3: Estimations and confidence intervals.