21.

Find the regression coefficient b_xy for the data $\sum \mathrm{x} = 32, \sum \mathrm{y} = 24, \sum \mathrm{xy} = 218, \sum {\mathrm{x}}^2 = 216, \sum {\mathrm{y}}^2 = 246$ and n = 8

• 0.3

• 0.7

• 0.8

• 0.6

If two regression coefficients are found to be - 0.6 and -1.4, the correlation coefficient will be

• 0.92

• 0.43

• - 0.43

• - 0.92

The iteration formula x_{n + 1} = x_n - $\frac{\mathrm{f}\left({\mathrm{x}}_{\mathrm{n}}\right)}{\mathrm{f}\text{'}\left({\mathrm{x}}_{\mathrm{n}}\right)}$ is commonly known as

• Bisection method

• Newton-Raphson method

• False-positions method

• None of the above

A gigabyte (GB) refers to

• 2¹⁰ bytes

• 2²⁰ bytes

• 2³⁰ bytes

• 2⁴⁰ bytes

Which of the following is a peripheral device?

• visual display unit

• Hard disk drive

• Floppy disk drive

• All of the above

Which of the following is not a general purpose application software ?

• Word processors

• Programs for playing games

• Spread-sheets

• Data communication software

The value of (1 + i)³ + (1 - i)⁶ is

• i

• 2(- 1 + 5i)

• 1 - 5i

• 2 + 1 - 5i

The equation of the normal to the hyperbola x² - 16y² - 2x - 64y - 72 = 0 at the point (- 4, - 3) is

• 5x + 16y + 79 = 0

• 16x + 5y + 97 = 0

• 16x + 5y + 79 = 0

• 5x + 16y + 97 = 0

Which of the following methods is surely convergent?

• Regula-Falsi method

• Balzano method

• Both (a) and (b)

• Neither (a) nor (b)

If A = $\left[\begin{array}{cc}1& \tan \left(\mathrm{x}\right)\\ - \tan \left(\mathrm{x}\right)& 1\end{array}\right]$, then the value of $\left|{\mathrm{A}}^{\mathrm{T}}{\mathrm{A}}^{- 1}\right|$ is

• $\cos \left(4\mathrm{x}\right)$

• ${\sec }^2\left(\mathrm{x}\right)$

• $- \cos \left(4\mathrm{x}\right)$

• 1