Durations of sunshine (in hours) in Amritsar for first 10 days of August 1997 as reported by the Meteorological Department are given below:
9.6, 5.2, 3.5, 1.5, 1.6, 2.4, 2.6, 8.4, 10.3, 10.9
(i) Find the mean 
(ii) Verify that 
= 0
Duration of sunshine (in hours) for 10 days are:
9.6, 5.2, 3.5, 1.5, 1.6, 2.4, 2.6, 8.4, 10.3, 10.9
(i) Mean, 
= 
= 
= 
= 5.6
(ii) L.H.S = 
= (x1 - 
) + (x2 - 
) + (x3 -
) + (x4 - 
) + ………. + (x10 - 
)
= (9.6 – 5.6) + (5.2 – 5.6) + (3.5 – 5.6) + (1.5 – 5.6) + (1.6 – 5.6) + (2.4 – 5.6)
= (4) + (-0.4) + (-2.1) + (-4.1) + (-4) + (-3.2) + (-3) + (2.8) + (4.7) + (5.3)
= 16.8 – 16.8
= 0
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