PSY201H5 Lecture Notes - Lecture 3: Percentile Rank, Linear Approximation, Central Tendency
Document Summary
Example: the percentile: draw a verticle line where it intersects this function from 80 y axis and 5 on x-axis we know its from 78-80 we want something more precise: linear relationship. This is not accumulative distribution: we don"t know precisely what the value is. Linear approximation of this cumulative freq histogram which we used to find the percentile rank of the score . Have to know the value of the slope and the intersect: you just plug intot he equation and u get y. How do u find the value of the slope: you use the two points and look at the difference btwn the y and x values= gives u slope of the line. Slope of the line is = upper value of the y / lower value of y: 4. 95 uppoer point, lower point 3. 45. Slide 15: answer 79. 21 ( same way but different mathematical expression)
