Final answer:
A scatter diagram's correlation type is determined by its data points, with a line upward indicating a positive correlation, a line downward a negative correlation, and no line indicating no correlation. The strength is defined by how closely data points cluster around a line, quantified by the correlation coefficient, r.
Step-by-step explanation:
The type of correlation a scatter diagram shows can be determined by analyzing the direction and density of the data points. If the data points seem to form a line going upwards from left to right, it suggests a positive correlation; if they form a line going downwards, it is a negative correlation. No apparent line suggests no correlation. To determine whether the correlation is strong or weak, you would assess how closely the data points follow this line. A correlation coefficient, r, quantifies this relationship. A value of r close to 1 or -1 indicates a strong relationship, whereas a value close to 0 indicates a weak relationship. For example, a scatter plot with r = .55 represents a moderately strong relationship. Hence, without the specific scatter plot examples, the general concept is that a close clustering of points along a slope indicates a strong correlation (whether positive or negative), and a more scattered distribution indicates a weaker correlation.
In summary, the correlation coefficient (r) indicates the strength and direction of the relationship. It is weakest (pointing towards no correlation) when it is closest to 0, and strongest when it is closer to 1 or -1, irrespective of whether it is positive or negative.