Question

Flexural strength is a measure of a material's ability to resist failure in bending. The accompanying data are on flexural strength of concrete (in MegaPascal, MPa, where 1 Pa (Pascal) = 1.45 ⨯ 10−4 psi):

5.9 7.2 7.3 6.1 8.1 6.8 7.0 7.6 6.8 6.5 7.0 6.3 7.9 9.0

8.2 8.7 7.8 9.7 7.4 7.7 9.7 7.8 7.7 11.6 11.4 11.8 10.7

(a) Construct a stem-and-leaf display of the data. (Enter numbers from smallest to largest separated by spaces. Enter NONE for stems with no values.)

Stems        /       Leaves

5

6

7

8

9

10

11

What appears to be a representative strength value? MPa

Do the observations appear to be highly concentrated about the representative value or rather spread out?

highly concentrated around the representative value

spread out with a large range

b) Does the display appear to be reasonably symmetric about a representative value, or would you describe its shape in some other way?

reasonably symmetric

positive skewness

negative skewness

completely random distribution

(c) Do there appear to be any outlying strength values?

Yes

No

d) What proportion of strength observations in this sample exceed 10 MPa? (Round your answer to two decimal places.)

Answer 1