Six different second-year medical students at Bellevue Hospital measured the blo
ID: 3124789 • 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?
137 129 133 146 129 136
Rangeequals=___mmHg
Sample variance=____mmHg2(Round to the nearest tenth as needed.)
Sample standard deviation=___mmHg (Round to the nearest tenth as needed.)
What should be the value of the standard deviation?
A. Ideally, the standard deviation would be one because this is the lowest standard deviation that can be achieved.
B. Ideally, the standard deviation would be one because all the measurements should be the same.
C.Ideally, the standard deviation would be zero because all the measurements should be the same.
D.There is no way to tell what the standard deviation should be.
Explanation / Answer
Ordering the data,
129
129
133
136
137
146
Hence,
RANGE = max - min = 146 - 129 = 17 [ANSWER]
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Getting the mean, X,
X = Sum(x) / n
Summing the items, Sum(x) = 810
As n = 6
Thus,
X = 135
Setting up tables,
x x - X (x - X)^2
137 2 4
129 -6 36
133 -2 4
146 11 121
129 -6 36
136 1 1
Thus, Sum(x - X)^2 = 202
Thus, as
s^2 = Sum(x - X)^2 / (n - 1)
As n = 6
s^2 = 40.4 [ANSWER, SAMPLE VARIANCE]
Thus,
s = 6.356099433 [ANSWER, SAMPLE STANDARD DEVIATION]
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OPTION C.Ideally, the standard deviation would be zero because all the measurements should be the same. [ANSWER]