The frequency distribution for the values of resistance in ohms of 56 resistors is as shown. Calculate the standard deviation from the mean of the resistors, correct to 4 significant figures. Draw histogram. 20.5-20.9 21.0-21.4 15 21.5-21.9 11 22.0-22.4 14 22.5-22.9 9 23.0-23.4 2

3. Cutting up a Wire A piece of wire is bent as shown in the figure. You can see that one cut through the wire produces four pieces and two parallel cuts produce seven pieces. How many pieces will be produced by 142 parallel cuts? Write a formula for the number of pieces produced by n parallel cuts.

Write and evaluate an expression of the form C(n, r) that represents each number of combinations of r cubes that can be taken from the eight cubes shown. (a) r = 1 (b) r = 2 (c) r = 3 (d) r = 4 (e) r = 5 (f) r = 6 (g) r = 7 (h) r = 8 II II II II

15 (-7- 7) -13 [7 - (-5 )]- 16 (-6 ) %3D

i 12345 Xi -4 -2 3 0 4 2 4 Yi -10.672 -6.428 -2.242 1.946 7.596

Evaluate A by expanding down the third column. 7 -3 -6 A = 4 0 -5 %3D 1 4 -2 A| = ( }A,3 + ( )A,3 +( )A3 A23+()A33 %3D |A| = (Simplify your answer.) %3D