Answer
a.
mean = 29.85
median = 29.5
mode = 24,26,37,38
b. 15% trimmed mean = 29.857
Work Step by Step
mean
= $(19+20+22+23+24+24+26+26+28+29+30+32+33+34+35+37+37+38+38+42)/20
= 29.85$
median = $(10th + 11th) / 2 = (29+30)/2 = 29.5$
15% trimmed mean, we remove 3 data from both ends and get
23,24,24,26,26,28,29,30,32,33,34,35,37,37
$trimmed \ mean =(23+24+24+26+26+28+29+30+32+33+34+35+37+37)/14
= 29.857$
