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Coding is a way of simplifying data to make it easier to work with. The coding must be carried out on all values within the data set and will normally be done using a given formula. Coding can be carried out in a number of ways: Adding or subtracting a constant to each data value.
To work out the estimate of the mean we need to know the mid- point of each time interval in the table. The time is also shown to the nearest minute. Therefore, for example, the interval 11 -20 is considered the interval 10.5 -20.5. To work out the mean we use the following formula: μ = ∑
Terms: central tendency, mode, median, mean, outlier Symbols: Mo, Mdn, M, m, ∑, N Learning Objectives: • Calculate various measures of central tendency—mode, median, and mean • Select the appropriate measure of central tendency for data of a given measurement scale and distribution shape
Coding: Note that you’d always calculate statistics like the mean on the coded data, not the original data. The idea is then you work out what this stat would be on the original data. e.g. If coding is = − 2, where original variable is and new coded one , we’d calculate say ̅, then add 2 to get the original mean ̅.
To calculate the arithmetic mean of a set of data we must first add up (sum) all of the data values. (x) and then divide the result by the number of values (n). Since. is the symbol used to indicate that values are to be summed (see Sigma Notation) we. obtain the following formula for the mean ( ̄x).
Averages, Means, Medians and Modes. Average is normally taken to be the ‘mean’, that is, the sum of a list of numbers, divided by the number of numbers in the list. Mean =. If you place the list of numbers in increasing order, the median is the number in the middle.
The mean can be described as a ―socialist‖ measure of central tendency, that is - the mean is the value that each participant receives if the sum is divided equally among all members of the group (Gravetter and Wallnau 2002). Students are well aware that the formula for the mean involves
