Question

Numerical Methods

Course Messages 0 out of t ports Question Which of the following commands in MATLAB will calculate the sum of all integers from 1 to 57 (choose all that apply) Question 0 out of 1 points Which of the following expressions is conventionally used to evaluate approximate relative error in percentage during iterative calculations? Note that subscript i is the iteration counter Question 10 1 out of 1 points What quantity is minimized during the least squares regression to fit sample data (xi, y) for i-1,.., n with a linear function fx)- Question 11 1 out of 1 points Repeating additions or subtractions by many iterations can accumulate round off error. Question 12 0 out of 1 points A sparse data set with high accuracy is suitable for interpolation rather than regression. Question 13 1 out of 1 points The following figures illustrate the difference of accuracy and precision. Which figure corresponds to data that are inaccurate and imprecise? Question 14 1 out of 1 points MATLAB command roots cannot find complex roots of a polynomial equation.

Answer 1

8). The following are the commands that can be used to compute sum till 'n' terms:

• sum till n terms can be calculated as   $\frac{n(n+1)}{2}$
• by using 'sum' command
• by using loops, viz., for loop, while loop

9). To find error we use,

$\frac{n_i-n_{i-1}}{n_{i-1}}*100$

10).

A Least Squares Regression Line is a straight line that describes how a response changes as an explanatory changes. The line is a mathematical model used to predict the value of y for a given x. The sum of the squared differences of observed values of the response variable and values of the response variable predicted by the model is the quantity which is minimized.

11).

Repeated addition or substraction will lead to round off errors.
For instance, if '0.01' is added to '21' six times, moreover if one significant number is selected, then we get 21.1, but correct value is 21.06. Thus, round off error increase because of repeated addition or substraction.