A traffic inspector has counted the number of vehicles passingthrough a certain point in 100 successive 20 – minute time periods.The observations are listed below.
23 | 20 | 16 | 18 | 30 | 22 | 26 | 15 | 5 | 18 |
14 | 17 | 11 | 37 | 21 | 6 | 10 | 20 | 22 | 25 |
19 | 19 | 19 | 20 | 12 | 23 | 24 | 17 | 18 | 18 |
27 | 16 | 28 | 26 | 15 | 29 | 19 | 35 | 20 | 17 |
12 | 30 | 21 | 22 | 20 | 15 | 18 | 16 | 23 | 24 |
15 | 24 | 28 | 19 | 24 | 22 | 17 | 19 | 8 | 18 |
17 | 18 | 23 | 21 | 25 | 19 | 20 | 22 | 21 | 23 |
16 | 20 | 19 | 11 | 23 | 17 | 23 | 13 | 17 | 26 |
26 | 14 | 15 | 16 | 27 | 18 | 21 | 24 | 33 | 20 |
21 | 27 | 18 | 22 | 17 | 20 | 14 | 21 | 22 | 10 |
You are required to:
a) Present these data on a grouped frequency distribution withclass width of 5 for each class starting with 5 to 9, 10 to 14 andsoon.                                   [5 marks]
b) Determine the real class limits and hence show the data on ahistogram. [5marks]
c) Estimate the (I) mean (ii) Mode and (iii)Median.      [4 + 6+6 = 10marks]
d) Estimate the (I) Quartiles (ii) Quartile Deviation (iii)Sample variance (iv) Sample standarddeviation.          [6 + 2 + 4 + 2 = 14 marks]
e) Find the (I) Coefficient of variation (ii) Coefficient ofSkewness.              [3 + 3 = 6 marks]
