**Core Concept:** Normal distribution curve, systolic blood pressure, mean, values above the mean

**Why the Correct Answer is Right:**
The systolic blood pressure (SBP) values of a group of individuals are assumed to follow a normal distribution, also known as Gaussian distribution. In this scenario, the mean SBP is given as 120 mmHg. When considering values above the mean, we are looking at the portion of the distribution that is to the right of the mean. In this case, the correct answer, option D, states that values above 120 mmHg are considered as such. This is because the mean (120 mmHg) is included in this range, and values above the mean are part of the distribution's tails.

**Why Each Wrong Option is Incorrect:**
A. This option is incorrect because values below the mean (120 mmHg) are not considered as "values above the mean."
B. This option is incorrect because it refers to values below the mean, not the values above the mean specified in the question.
C. This option is incorrect because it refers to values below the mean, not the values above the mean specified in the question.

**Clinical Pearl / High-Yield Fact:**
Understanding the normal distribution of blood pressure is crucial in clinical practice, particularly when interpreting individual patient data or making decisions regarding population-based interventions. It highlights the concept of central tendency, dispersion, and the role of the mean and standard deviation in defining the distribution.

**Correct Answer:** D (Values above the mean)

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**Question:** Systolic blood pressure of a group of persons follows normal distribution curve. The distribution is characterized by a mean and a standard deviation. If the mean SBP is 120 mmHg and the standard deviation is 10 mmHg, then the range of SBP values is from what limits?

**Core Concept:** Normal distribution, mean, standard deviation, range

**Why the Correct Answer is Right:**
The normal distribution curve is characterized by two key parameters: the mean and the standard deviation. To determine the range of systolic blood pressure (SBP) values, we need to find the limits of the distribution. In this scenario, the mean SBP (120 mmHg) and the standard deviation (10 mmHg) are provided. The range of SBP values is determined by subtracting the lower limit from the upper limit.

**Why Each Wrong Option is Incorrect:**
A. This option is incorrect because it only considers the mean but does not take into account the standard deviation, which represents the spread of the distribution. The range would be wider than the provided value.
B. This option is incorrect because it only considers the mean but does not take into account the standard deviation, which represents the spread of the distribution. The range would be narrower than the provided value.
C. This option is incorrect because it only considers the mean but does not take into account the standard deviation, which represents the spread of the distribution. The range would be wider than the provided value.
D. This option is incorrect because it only considers the mean but does not take into account the standard deviation, which represents the