Math Problem Statement

The values of two variables, measured for nine different items, are shown in the table. (a) Use technology to plot the data on a scatter graph. (b) Describe the correlation suggested by the graph. (c) Calculate Pearson's product-moment correlation coefficient. (d) The critical value of the correlation coefficient for nine items is 0.521. Do the data suggest that there is significant correlation between the two variables?

Solution

a) Scatter Plot

The scatter plot of xx vs yy is shown above. It displays how the two variables are related visually.

b) Description of the Correlation

The scatter plot does not show a clear linear relationship. The points are fairly scattered, and the trend appears to be slightly negative, meaning that as xx increases, yy tends to decrease, but the correlation is not strong.

c) Pearson's Product-Moment Correlation Coefficient

The calculated Pearson's correlation coefficient is approximately r=0.480r = -0.480. This suggests a weak negative correlation between the two variables.

d) Significance of the Correlation

The critical value for the correlation coefficient for nine items is 0.521. Since the absolute value of our calculated rr (0.480) is less than the critical value (0.521), we conclude that the data does not suggest a statistically significant correlation between the two variables.


Would you like any further explanation or details?

Here are five related questions to expand on this topic:

  1. How is Pearson's correlation coefficient interpreted in general?
  2. What are some limitations of using correlation to infer relationships?
  3. How can outliers affect the correlation coefficient?
  4. What is the difference between correlation and causation?
  5. How can the significance of correlation be tested using different methods?

Tip: Always ensure that you have enough data points and that they are well-distributed when interpreting correlation results to avoid misleading conclusions.

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Math Problem Analysis

Mathematical Concepts

Correlation
Pearson's correlation
Scatter plot
Statistical significance

Formulas

Pearson's correlation coefficient formula

Theorems

Critical value theorem for correlation coefficients

Suitable Grade Level

Grades 10-12