Question

Dataset ex01-20 is available here.
The article "Determination of Most Representative Subdivision" (J. of Energy Engr., 1993: 43-55) gave data on various characteristics of subdivisions that could be used in deciding whether to provide electrical power using overhead lines or underground lines. Here are the values of the variable x = total length of streets within a subdivision.

1280	5320	4390	2100	1240	3060	4770
1050	360	3330	3380	340	1000	960
1320	530	3350	540	3870	1250	2400
960	1120	2120	450	2250	2320	2400
3150	5700	5220	500	1850	2460	5850
2700	2730	1670	100	5770	3150	1890
510	240	396	1419	2109

(a) Construct a stem-and-leaf display by truncating the data and using the thousands digit as the stem and the hundreds digit as the leaf, and comment on the various features of the display. (Enter your answers from smallest to largest. Enter NONE in any unused answer blanks.)

Stem	Leaf (units=hundreds)
0	1
1	2
2	3
3	4
4	5
5	6

Comment (pick the right choice (s) from below) :

a) A typical data value is somewhere in the low 3000's.

b) The display is almost unimodal and has a negative skew.

c) A typical data value is somewhere in the low 2000's.

d) The display is almost unimodal and symmetric.

e) A typical data value is somewhere in the high 1000's.

f) The display is almost unimodal and has a positive skew.

(b) Construct a histogram using class boundaries 0, 1000, 2000, 3000, 4000, 5000, and 6000. (Do this on paper. Your instructor may ask you to turn in this work.) What proportion of subdivisions have total length less than 2000? (Enter your answer to three decimal places.)


What proportion of subdivisions have total length between 2000 and 4000? (Enter your answer to three decimal places.)

How would you describe the shape of the histogram? (one or more may be correct)

a) The display is almost unimodal and has a positive skew.

b) The display is almost unimodal and has a negative skew.

c) A typical data value is somewhere in the low 3000's.

d) A typical data value is somewhere in the low 2000's.

e) A typical data value is somewhere in the high 1000's.

f) The display is almost unimodal and symmetric.

Answer 1