2. (a) Differentiate between primary and secondary mental abilities. How the general mental ability scales differ from IQ test. (b) Y = mX + C is an equation of straight line. Draw a graph showing relationship between X and Y and relate the equation to the slope and intercept on the graph.

(a)

• Primary mental abilities are basic cognitive abilities that underlie a wide range of tasks, such as verbal comprehension, spatial ability, perceptual speed, numerical ability, memory, and reasoning. These abilities are relatively independent of each other and can be measured individually.
• Secondary mental abilities are broader cognitive abilities that are derived from combinations of primary mental abilities, such as fluid intelligence (the ability to solve novel problems) and crystallized intelligence (the ability to use acquired knowledge and skills).
• General mental ability (GMA) scales are designed to measure overall cognitive ability, or intelligence, by assessing a range of mental abilities that are related to academic and work performance. While IQ tests are a type of GMA scale, they typically focus more on measuring verbal and quantitative abilities, while other GMA scales may also include measures of spatial and perceptual abilities.

(b) The equation of a straight line, Y = mX + C, represents a linear relationship between two variables, X and Y. The slope of the line (m) represents the rate of change of Y for each unit change in X, while the intercept (C) represents the value of Y when X equals zero.

To draw a graph showing the relationship between X and Y, we can plot pairs of values for X and Y and connect the points with a straight line. If we assume, for example, that m = 2 and C = 1, the equation becomes Y = 2X + 1. This means that for each unit increase in X, Y increases by two units and the line crosses the Y-axis at the point (0,1).

On the graph, the slope is represented by the angle of the line with respect to the X-axis. A steeper line indicates a larger slope, which means that changes in X have a greater effect on Y. The intercept is represented by the point where the line crosses the Y-axis. This point indicates the starting value of Y when X is zero.