Math Problem Statement
use the picture above of the critical values for the pearson correlation coefficient to answer the question. find the regression equation, letting the systolic reading be the independent (x) variable. if one of these people has a systolic blood pressure of 137 mm Hg. What is the best predicted diastolic blood pressure? Round regression equation to two decimal places as needed. Round best predicted diastolic blood pressure to one decimal place as needed. The systolic blood pressure data in respective order is as follows : 122, 134, 143, 140, 135, 113, 110, 145. the diastolic blood pressure data in respective order is as follows : 62, 71, 80, 80, 100, 59, 82, 105.
Solution
To find the regression equation and the best predicted diastolic blood pressure given the systolic data, we will go through these steps:
Step 1: Compute the correlation coefficient
We will calculate the correlation coefficient between systolic and diastolic blood pressure. Using Pearson's correlation formula:
[ r = \frac{n\sum xy - (\sum x)(\sum y)}{\sqrt{[n\sum x^2 - (\sum x)^2][n\sum y^2 - (\sum y)^2]}} ]
Where:
- is the number of data points,
- is the systolic blood pressure values, and
- is the diastolic blood pressure values.
The systolic and diastolic values are:
- : 122, 134, 143, 140, 135, 113, 110, 145
- : 62, 71, 80, 80, 100, 59, 82, 105
Step 2: Calculate the slope and intercept of the regression line
The regression line is represented as: Where:
- is the slope, and
- is the intercept.
Step 3: Predict the diastolic pressure for a systolic pressure of 137 mm Hg
Once the regression equation is determined, substitute into the equation to predict the diastolic pressure.
Let's proceed by calculating each of these values.### Step 1: Pearson's Correlation Coefficient The calculated correlation coefficient , indicating a moderate positive correlation between systolic and diastolic blood pressure.
Step 2: Regression Equation
The regression equation, rounded to two decimal places, is: Where is the systolic blood pressure, and is the predicted diastolic blood pressure.
Step 3: Predicted Diastolic Pressure for a Systolic Pressure of 137 mm Hg
Using the equation , the best predicted diastolic blood pressure is approximately:
Would you like further details on any of these calculations, or do you have additional questions?
Here are some related questions to consider:
- How does changing the systolic value affect the diastolic prediction?
- What are the implications of a correlation coefficient close to 1 or -1?
- What other methods can be used to predict diastolic pressure based on systolic pressure?
- How can the accuracy of this regression model be evaluated?
- What are the limitations of using linear regression for this dataset?
Tip: In regression analysis, checking the residuals (differences between actual and predicted values) helps to evaluate the model's accuracy.
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Math Problem Analysis
Mathematical Concepts
Statistics
Correlation
Linear Regression
Formulas
Pearson's correlation coefficient: r = (nΣxy - (Σx)(Σy)) / sqrt([nΣx^2 - (Σx)^2][nΣy^2 - (Σy)^2])
Regression equation: y = a + bx
Slope formula: b = (nΣxy - ΣxΣy) / (nΣx^2 - Σx^2)
Intercept formula: a = ȳ - bẋ
Theorems
Pearson's correlation coefficient theorem
Least squares regression
Suitable Grade Level
College-level statistics
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