central tendency.pptx nursing research ppt

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1. Central Tendency To identify the center of a distribution than from an extreme

2. Mean Measure arithmetic mean by summing up all the observations and dividing the total by the number of observations. The mean is the most widely used measure of central tendency Many statistical tests depends on mean. Useful in interval and ratio level measurement.

3. Uses of Mean Helps to find out how the normal observations lying close to central value while few of the too large or too small lie for away at both the ends. To find which group is better by comparing the average. Used when no extreme value in the data set. To calculate other tests.

4. Median The Median is the point in a distribution above which and below which 50% of cases fall. For ungroup even number of data, arrange the data from highest to lowest or vise versa and median is N/2 th position and for ungroup odd data N+1/2 th positioned score is median . Median is better measurement of central tendency than mean in an unevenly distributed scores.

5. Uses of median To find out midpoint of given distribution Used when the series contains extremes scores

6. Mode It is most frequently occurring score value in distribution Modes are quick way to determine a popular score. But it is unstable because it can fluctuate Primarily used for nominal level measurement.

7. Uses of Mode Not affected by extreme value Can be used to describe qualitative and quantitative data. But not used for further any calculations.

8. Measures of variability It helps to find out how individual observation are dispersed around the mean of a large series. Also known as measures of dispersion.

9. Measures of variations Range: distance Between lowest and highest data point. Mean deviation: avarage of deviation scores Variance: relationship between mean and the data points. Standard deviation: square root of the variance

10. Uses of SD Indicates whether the difference between the mean and the individual is real or by chance. Find out whether the difference between two sample mean is real or by chance. Help to find out the standard error. Difference between sample mean and population mean. Helps to find out suitable sample size. Helps in different statistical calculations.

11. Standard deviation0