Basic Descriptive statistics
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Descriptive statistics is used to describe and summarize key characteristics of a data set. Commonly used measures include central tendency, such as the mean, median, and mode, and measures of dispersion like range, interquartile range, standard deviation, and variance. The mean is the average value calculated by summing all values and dividing by the number of values. The median is the middle value when data is arranged in order. The mode is the most frequently occurring value. Measures of dispersion describe how spread out the data is, such as the difference between highest and lowest values (range) or how close values are to the average (standard deviation).
Basic Descriptive statistics
- 1. Basic Statistics : Descriptive Statistics
- 2. What is Descriptive Statistics ? “ This is the statistics which deals with descriptive section of the data set as well as have tendency to describe the data set initially ”
- 3. Commonly used measures to describe a data set : Measures of Central Tendency Measures of dispersion
- 4. Measures of Central Tendency: A measure of central tendency is a single value that attempts to describe a set of data by identifying the central position within that set of data. The mean, median and mode are most likely the measures of central tendency that we are most familiar with. Mean (Arithmetic) : The mean (or average ) is equal to the sum of all the values in the data set divided by the number of values in the data set. So, if we have n values in a data set and they have values x1, x2, ..., xn, the sample mean, usually denoted by (pronounced x bar), is:
- 5. Median The median is the middle score for a set of data that has been arranged in order of magnitude. Mode : The mode is the value that appears most often in a set of data.
- 6. Measures of dispersion Range: The spread, or the distance, between the lowest and highest values of a variable. Interquartile Range: A quartile is the value that marks one of the divisions that breaks a series of values into four equal parts. The Interquartile range is the distance or range between the 25th percentile and the 75th percentile.
- 7. Standard Deviation: The standard deviation gives an idea of how close the entire set of data is to the average value. Variance: Measures how far a set of numbers is spread out. A variance of zero indicates that all the values are identical. Variance is always non-negative, a small variance indicates that the data points tend to be very close to the mean (Average value), while a high variance indicates that the data points are very spread out around the mean.
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