Concept:Mean deviation is the average of the absolute differences between each data value and the arithmetic mean.Explanation:The given data are:20,30,25,40,35,50,45,40,20,45Number of observations, n=10Sum of observations, ∑x=350Mean, xˉ=n∑x=10350=35Find each absolute deviation ∣x−xˉ∣:∣20−35∣=15, ∣30−35∣=5, ∣25−35∣=10, ∣40−35∣=5, ∣35−35∣=0∣50−35∣=15, ∣45−35∣=10, ∣40−35∣=5, ∣20−35∣=15, ∣45−35∣=10Total absolute deviation, ∑∣x−xˉ∣=15+5+10+5+0+15+10+5+15+10=90Mean deviation =n∑∣x−xˉ∣=1090=9
