ผลต่างระหว่างรุ่นของ "Probstat/homework 2"
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== Part 2: Distribution of sample means. == | == Part 2: Distribution of sample means. == | ||
− | 2.1 | + | 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 | + | (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>. |
− | + | (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. | + | 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>. |
− | + | 2.3 Find <math>P\{\bar{X} > 11\}</math>. (Hint: use the standard normal table to find the answer.) | |
− | + | 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.
- work on Week 8 practice 2, basic practice, questions 2,4,6,8, and 10.
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.)