(b) Use rules of variance to obtain an expression for the variance and standard deviation (standard error) of the estimator in part (a). v(x-7)= v(x+v(n = 0,² +0,² Identify the next step in this rule from the options below. 2 0 x-5-² X-5-02-02 --- --- Since standard deviation is the square root of variance, it follows that 0₂
(b) Use rules of variance to obtain an expression for the variance and standard deviation (standard error) of the estimator in part (a). v(x-7)= v(x+v(n = 0,² +0,² Identify the next step in this rule from the options below. 2 0 x-5-² X-5-02-02 --- --- Since standard deviation is the square root of variance, it follows that 0₂
MATLAB: An Introduction with Applications
6th Edition
ISBN:9781119256830
Author:Amos Gilat
Publisher:Amos Gilat
Chapter1: Starting With Matlab
Section: Chapter Questions
Problem 1P
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![### Statistical Analysis: Variance and Standard Deviation Computation
#### (b) Variance and Standard Deviation (Standard Error) Computation
Use the rules of variance to obtain an expression for the variance and standard deviation (standard error) of the estimator in part (a):
\[ V(\overline{X} - \overline{Y}) = V(\overline{X}) + V(\overline{Y}) = \frac{\sigma_{X}^{2}}{n_{1}} + \frac{\sigma_{Y}^{2}}{n_{2}} \]
Identify the next step in this rule from the options below:
- \( \bigcirc \) \( V(\overline{X} - \overline{Y}) = \frac{\sigma_{1}^{2}}{n_{1}} + \frac{\sigma_{2}^{2}}{n_{2}} \)
- \( \phantom{\bigcirc} \) \( V(\overline{X} - \overline{Y}) = \frac{\sigma_{1}^{2}}{n_{1}} - \frac{\sigma_{2}^{2}}{n_{2}} \)
- \( \phantom{\bigcirc} \) \( V(\overline{X} - \overline{Y}) = \frac{\sigma_{1}}{n_{1}} + \frac{\sigma_{2}}{n_{2}} \)
- \( \phantom{\bigcirc} \) \( V(\overline{X} - \overline{Y}) = \frac{\sigma_{1}}{n_{1}} - \frac{\sigma_{2}}{n_{2}} \)
Since standard deviation is the square root of variance, it follows that:
\[ \sigma_{\overline{X} - \overline{Y}} = \sqrt{V(\overline{X} - \overline{Y})} \]
- \( \phantom{\bigcirc} \) \( \sigma_{\overline{X} - \overline{Y}} = \sqrt{\frac{\sigma_{1}^{2}}{n_{1}} - \frac{\sigma_{2}^{2}}{n_{2}}} \)
- \( \bigcirc \) \( \sigma_{\overline{X} - \overline{Y}} = \sqrt{\frac{\sigma_{1}^{2}}](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2Feeb0cd63-fcaf-4f78-a653-01ec8225914a%2F98116f40-0855-410a-93ef-ccf2c734b0fa%2F62smxrs_processed.png&w=3840&q=75)
Transcribed Image Text:### Statistical Analysis: Variance and Standard Deviation Computation
#### (b) Variance and Standard Deviation (Standard Error) Computation
Use the rules of variance to obtain an expression for the variance and standard deviation (standard error) of the estimator in part (a):
\[ V(\overline{X} - \overline{Y}) = V(\overline{X}) + V(\overline{Y}) = \frac{\sigma_{X}^{2}}{n_{1}} + \frac{\sigma_{Y}^{2}}{n_{2}} \]
Identify the next step in this rule from the options below:
- \( \bigcirc \) \( V(\overline{X} - \overline{Y}) = \frac{\sigma_{1}^{2}}{n_{1}} + \frac{\sigma_{2}^{2}}{n_{2}} \)
- \( \phantom{\bigcirc} \) \( V(\overline{X} - \overline{Y}) = \frac{\sigma_{1}^{2}}{n_{1}} - \frac{\sigma_{2}^{2}}{n_{2}} \)
- \( \phantom{\bigcirc} \) \( V(\overline{X} - \overline{Y}) = \frac{\sigma_{1}}{n_{1}} + \frac{\sigma_{2}}{n_{2}} \)
- \( \phantom{\bigcirc} \) \( V(\overline{X} - \overline{Y}) = \frac{\sigma_{1}}{n_{1}} - \frac{\sigma_{2}}{n_{2}} \)
Since standard deviation is the square root of variance, it follows that:
\[ \sigma_{\overline{X} - \overline{Y}} = \sqrt{V(\overline{X} - \overline{Y})} \]
- \( \phantom{\bigcirc} \) \( \sigma_{\overline{X} - \overline{Y}} = \sqrt{\frac{\sigma_{1}^{2}}{n_{1}} - \frac{\sigma_{2}^{2}}{n_{2}}} \)
- \( \bigcirc \) \( \sigma_{\overline{X} - \overline{Y}} = \sqrt{\frac{\sigma_{1}^{2}}

Transcribed Image Text:### Comparing Flexural Strength of Concrete Beams and Cylinders
#### Flexural Strength Data of Concrete Beams
The flexural strength (MPa) for concrete beams of a certain type is given in the following table:
| 5.3 | 7.2 | 7.3 | 6.3 | 8.1 | 6.8 | 7.0 | 7.4 | 8.6 | 6.5 | 7.0 | 6.3 | 7.9 | 9.0 | 8.6 | 8.7 | 7.8 | 7.4 | 7.7 | 7.7 | 9.7 | 7.6 | 8.6 | 7.5 | 9.7 | 8.6 | 7.8 | 7.0 | 11.4 | 7.1 | 8.6 | 8.6 | 8.6 | 10.4 | 11.6 | 11.3 | 11.8 | 11.8 | 10.7 |
#### Strength Observations for Cylinders
The strength for cylinders is recorded in the following table:
| 6.7 | 5.8 | 7.8 | 7.1 | 7.2 | 9.2 | 6.6 | 8.3 | 7.0 | 8.1 | 7.2 | 8.1 | 7.4 | 8.5 | 8.9 | 9.8 | 9.4 | 7.1 | 12.1 | 12.6 | 11.0 |
### Statistical Analysis
#### Part (a): Bias and Estimation
- **Objective**: Determine if \(\bar{X} - \bar{Y}\) is an unbiased estimator of \(\mu_1 - \mu_2\).
Let \(\bar{X}\) denote the mean strength for beams and \(\bar{Y}\) for cylinders, where \(\{X_i\}\) is a random sample from distribution with mean \(\mu_1\) and standard deviation \(\sigma_1\), and \(\{Y_i\}\) is from another distribution with mean \(\mu_2\) and
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