Question 1083078: Measurements were taken of the weight (to the nearest 5 Kg’s) of 100 individuals from a certain population. The results are shown in the table below.
Weight (Kg) Number of Individuals
50 1
55 8
60 19
65 38
70 22
75 10
80 2
(i) Find the mean, median and mode of this data set.
(ii) Find the standard deviation and variance.
Answer by Boreal(15235)   (Show Source):
You can put this solution on YOUR website! 50 1 =50
55 8 =440
60 19 =1140
65 38 =2470
70 22 =1540
75 10 =750
80 2=160
sum is 6550
mean is that divided by 100 or 65.5 kg
median is between 50th and 51st, which is 65 kg
mode is most common or 65 kg
variance is (-15)^2*1=225
+(-10^2)*8=800
25*19=475
+0
+550
1000
+450
Adds to 3500
if population, divide by 100 and variance is 35 and sd is its sqrt, or 5.92 kg
If sample, divide by 99 and variance is 35.35 and sd is 5.95 kg.
I am not taking the middle of 50 and 55, because these are to the nearest 5 kg, which makes each group centered on a kg evenly divisible by 5.
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