Six different second-year medical students at Bellevue Hospital measured the blo
ID: 3134115 • Letter: S
Question
Six different second-year medical students at Bellevue Hospital measured the blood pressure of the same person. The systolic readings (in mmHg) are listed below. Find the range, variance, and standard deviation for the given sample data. If the subject's blood pressure remains constant and the medical students correctly apply the same measurement technique, what should be the value of the standard deviation?
138 142 123 144 126 140
what is the range mmHg
Open in StatCrunch Copy to Clipboard + Open in ExcelExplanation / Answer
Ordering the data,
123
126
138
140
142
144
Also, we have
Maximum = 144
Minimum = 123
Range = max - min = 21 [ANSWER, RANGE]
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Getting the mean, X,
X = Sum(x) / n
Summing the items, Sum(x) = 813
As n = 6
Thus,
X = 135.5
Setting up tables,
x x - X (x - X)^2
123 -12.5 156.25
126 -9.5 90.25
138 2.5 6.25
140 4.5 20.25
142 6.5 42.25
144 8.5 72.25
Thus, Sum(x - X)^2 = 387.5
Thus, as
s^2 = Sum(x - X)^2 / (n - 1)
As n = 6
s^2 = 77.5 [ANSWER, VARIANCE]
Thus,
s = 8.803408431 [ANSWER, STANDARD DEVIATION]