MEASURES OF POSITION

• Measures of Position - used to locate the relative position of a data value in the data set.
• Quartiles - the three score points which is divide a distribution into four equal parts.
• The score points in quartiles are denoted as; Q1, Q2, Q3
• Q1 - called to the lower quartile
• Q3 - called to the upper quartile
• Q2 - coincides with the median
• Interquartile range - the difference between Q3 and Q1
• To determine the quartile, the data must be arranged from lowest to highest. Then apply the Mendenhall and Sincich Method.
• Lower quartile (L) formula: Position of Q1 = 1/4 (n+1)
• Upper Quartile (U) formula: Position of Q3 = 3/4 (n+1). where n is the number of data.
• The two data elements always used in Mendenhall and Sincich Method are: Lower quartile (Q1) and Upper quartile (Q3)
• True or False. After getting the answer in Mendenhall and Sincich Method, always round to the nearest integer. True
• Deciles - the nine score points which divide a distribution into ten equal parts.
• The score points in decile are denoted as; D1, D2, D3, ... D9
• To find the position in decile, use the formula: k/10 (n+1). where k is the desired data and n is the number of data.
• Percentiles - the ninety-nine score points which divide a distributioninto one hundred equal parts.
• The score points in percentile are denoted as; P1, P2, P3, ... P99
• The formula for percentile is: k/100 (n+1). where k is the desired percentile and n is the number of data.