CHAPTER 2:Visual Description of Data Part 1to accompanyIntroduction to Business Statisticsfourth edition, by Ronald M. WeiersPresentation by Priscilla Chafe-StengelDonald . Stengel ! "##" $he Wads%orth &roup Capter 2 ! "earnin# $%&ecti'es'Con(ert ra% data into a data array.'Construct)*a fre+uency distribution.*a relati(e fre+uency distribution.*a cumulati(e relati(e fre+uency distribution.'Construct a stem-and-leaf diagram.',isually represent data by using graphs and charts.! "##" $he Wads%orth &roup Capter 2 ! (e) Ter*s'Data array*-n orderly presentation of data in either ascending or descending numerical order.'.re+uency Distribution*- table that represents the data in classes and that sho%s the number of obser(ations in each class.! "##" $he Wads%orth &roup Capter 2 ! (e) Ter*s'.re+uency Distribution*Class - $he category*Frequency - umber in each class*Class limits - /oundaries for each class*Class interval - Width of each class*Class mark - Midpoint of each class! "##" $he Wads%orth &roup Stur#es+ rule'0o% to set the appro1imate number of classes to %e#in constructing a fre+uency distribution.%here , 2 appro1imate number of classes to use andn 2 the number of obser(ations in the data set .! "##" $he Wads%orth &roupk n = + 1 332210. (log ) Alternati'es to Stur#es+ Rule'3se the s+uare root of n 4the number of obser(ations5 as the number of cells*Simpler to use for n 6 7# *Poor for larger (alues of n'3se the formula) n 2 "c %here c 4the po%er of "5 is the number of cells to use. $his method gi(es the same result as Sturge8s rule minus 9. Ho- to Construct aFrequency Distribution1. Number of classesChoose an appro1imate number of classes for your data.Sturges8 rule can help.2. Estimate the class interval Di(ide the appro1imate number of classes .fro* Step 1/ into the range of your data to :nd the appro1imate class inter(al, %here the range is de:ned as the largest data (alue minus the smallest data (alue.3. Determine the class intervalRound the estimate .fro* Step 2/ to a con(enient (alue.! "##" $he Wads%orth &roup Ho- to Construct aFrequency Distribution, cont04. Loer Class LimitDetermine the lo%er class limit for the :rst class by selecting a con(enient number that is smaller than the lo%est data (alue. !. Class LimitsDetermine the other class limits by repeatedly adding the class %idth .fro* Step 2/ to the prior class limit, starting %ith the lo%er class limit .fro* Step 1/.". De#ne the classes3se the se+uence of class limits to de:ne the classes.! "##" $he Wads%orth &roup Con'ertin# to a Relative Frequency Distribution9. Retain the same classes de:ned in the fre+uency distribution.". Sum the total number of obser(ations across all classes of the fre+uency distribution.;. Di(ide the fre+uency for each class by the total number of obser(ations, forming the percentage of data (alues in each class.! "##" $he Wads%orth &roup 2or*in# a Cumulative Relative Frequency Distribution9.