Question

Concrete"T). MOE 29.8 33.2 33.7 35.3 35.5 36.1 36.2 36.3 37.5 37.7 38.7 38.8 39.6 41.0 Strength 5.9 7.2 7.3 6.3 8.1 6.8 7.0 7.6 6.8 6.5 7.0 6.3 7.9 9.0 MOE 42.8 42.8 43.5 45.6 46.0 46.9 48.0 49.3 51.7 62.6 69.8 79.5 80.0 Strength 8.2 8.7 7.8 9.7 7.4 7.7 9.7 7.8 7.7 11.6 11.3 11.8 10.7 (a) Construct a stem-and-leaf display of the MOE values. (Round each value down to the nearest whole number. Enter numbers from smallest to largest separated by spaces. Enter NONE for stems with no values. Split the stems, placing leaves 0 to 4 on the first stem and leaves 5 to 9 on the second stem of the same value. Use the tens digit as the stem and the ones digit as the leaf.) stem leaf 2 2 3 3 4 4 5 5 6 6 7 7 8 8
Values of modulus of elasticity (MOE, the ratio of stress, i.e., force per unit area, to strain, i.e., deformation per unit length, in GPa) and flexural strength (a measure of the ability to resist failure in bending, in MPa) were determined for a sample of concrete beams of a certain type, resulting in the following data (read from a graph in the article "Effects of Aggregates and Microfillers on the Flexural Properties of Concrete"†).

Answer 1

Ans a ) the stem and leaf display is

Stem-and-Leaf Display: MOE

Stem-and-leaf of MOE N = 25
Leaf Unit = 1.0

1 2
1 2 9
3 3 33
12 3 566677889
(4) 4 1223
9 4 5689
5 5 1
4 5
4 6 2
3 6 9
2 7
2 7 9
1 8 0

option A and E are true

b ) option A is true

c ) y = 3.2925+0.10748 x

for x= 37

predicted strengt = 3.2925+0.10748*37 =7.27

for x = 100

y = 3.2925+0.10748*100 = 14.04

option D is true

d )

SSE	18.736
SST	71.605
r^2	0.738

option b is true