MONTHLY STARTING SALARY (In TRL)

Graduate Monthly Starting Salary

1 2,850

2 2,950

3 3,050

4 2,880

5 2,755

6 2,710

7 2,890

8 3,130

9 2,940

10 3,325

11 2,920

12 2,880

TOTAL: 35,280

Properties of the Mean

1- The Mean can be calculated for any set of NUMERICAL Data2- The Mean is unique and unambiguous value.3- The means of several sets of data can always be combined into the overall mean of all the data.4- If each value in a sample were replaced by the mean, then ∑X would remain unchanged5- The mean takes into account the value of each item in a set of data.6- The mean is relatively reliable in the sense that means of many samples drawn from the same population generally do not fluctuate, or vary, as widely as other statistics used to estimate the mean of a population.

Properties of the Median

In addition to the properties of the Mean;

1- It splits the data into two parts2- The median is preferable to the mean because it is not so easily affected by extreme values.

Problem: Imagine that four classes in Math 264 course obtained the following mean scores on the final examination; 75, 78, 72 and 80. Q: Could you sum these four means together and divide by 4 to obtain an overall mean for all of the four classes?

A: This could be done only if the n (the number of students) in each class is identical

What if;First Class = 30 studentsSecond Class= 40 studentsThird Class= 25 studentsFourth Class= 50 students

Then the weighted mean is =?

Problem: The following list gives the duration in minutes of 24 power failures. (Chapter 3. Exercise: 31)

18 125 44 96 31 5326 80 49 125 63 5845 33 89 12 103 12775 40 80 61 28 129 Find the median.