# 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.