In: Statistics and Probability
17, 18, 18, 18, 19, 20, 20, 20, 20, 21, 21, 21, 21, 22, 22, 22, 22, 22, 22, 23,23, 24,24,24,24,24,24,24,24,25,26,26,26,26,26,26,27,27,27,27,27,28,28,29,31,31,32,32,34,35,38 use the data to do the following: 1. sample mean 2. median 3. mode 4. standard deviation
The answers are:
1. Sample Mean | 24.66667 |
2. Median | 24 |
3. Mode | 24 |
4. Standard Deviation | 4.594199 |
Calculations:
Consider the following table:
Data | Frequency | Data * Frequency | (X - Mean) * Frequency | (X - Mean)^2 * Frequency |
17 | 1 | 17 | -7.6667 | 58.7778 |
18 | 3 | 54 | -20.0000 | 133.3333 |
19 | 1 | 19 | -5.6667 | 32.1111 |
20 | 4 | 80 | -18.6667 | 87.1111 |
21 | 4 | 84 | -14.6667 | 53.7778 |
22 | 6 | 132 | -16.0000 | 42.6667 |
23 | 2 | 46 | -3.3333 | 5.5556 |
24 | 8 | 192 | -5.3333 | 3.5556 |
25 | 1 | 25 | 0.3333 | 0.1111 |
26 | 6 | 156 | 8.0000 | 10.6667 |
27 | 5 | 135 | 11.6667 | 27.2222 |
28 | 2 | 56 | 6.6667 | 22.2222 |
29 | 1 | 29 | 4.3333 | 18.7778 |
31 | 2 | 62 | 12.6667 | 80.2222 |
32 | 2 | 64 | 14.6667 | 107.5556 |
34 | 1 | 34 | 9.3333 | 87.1111 |
35 | 1 | 35 | 10.3333 | 106.7778 |
38 | 1 | 38 | 13.3333 | 177.7778 |
Total | 51 | 1258 | 0.00 | 1,055.3333 |
Median is corresponding to the 26th position element = 24
Mode = Most common observation = 24
Hence
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