X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=doc%2Fstatistics.texi;h=1e24c173516bcfa62ebb8d8af0ad432e3d1d9a34;hb=ab97e700f033db654e2f44919c73973d13b0c522;hp=f0160f40a8a2888b626c4f61f00ca3c15758a216;hpb=5443c41f89a2b29cf8cf55f21eecb839fae08177;p=pspp diff --git a/doc/statistics.texi b/doc/statistics.texi index f0160f40a8..1e24c17351 100644 --- a/doc/statistics.texi +++ b/doc/statistics.texi @@ -138,6 +138,7 @@ FREQUENCIES [@{FREQ,PERCENT@}] [@{NOMISSING,MISSING@}] /BARCHART=[MINIMUM(@var{x_min})] [MAXIMUM(@var{x_max})] [@{FREQ,PERCENT@}] + /ORDER=@{ANALYSIS,VARIABLE@} (These options are not currently implemented.) @@ -148,9 +149,8 @@ FREQUENCIES The @cmd{FREQUENCIES} procedure outputs frequency tables for specified variables. @cmd{FREQUENCIES} can also calculate and display descriptive statistics -(including median and mode) and percentiles, -@cmd{FREQUENCIES} can also output -histograms and pie charts. +(including median and mode) and percentiles, and various graphical representations +of the frequency distribution. The @subcmd{VARIABLES} subcommand is the only required subcommand. Specify the variables to be analyzed. @@ -197,9 +197,12 @@ For instance, @subcmd{/NTILES=4} would cause quartiles to be reported. The @subcmd{HISTOGRAM} subcommand causes the output to include a histogram for each specified numeric variable. The X axis by default ranges from the minimum to the maximum value observed in the data, but the @subcmd{MINIMUM} -and @subcmd{MAXIMUM} keywords can set an explicit range. The number of -bins are 2IQR(x)n^-1/3 according to the Freedman-Diaconis rule. (Note that -@cmd{EXAMINE} uses a different algorithm to determine bin sizes.) +and @subcmd{MAXIMUM} keywords can set an explicit range. +@footnote{The number of +bins is chosen according to the Freedman-Diaconis rule: +@math{2 \times IQR(x)n^{-1/3}}, where @math{IQR(x)} is the interquartile range of @math{x} +and @math{n} is the number of samples. Note that +@cmd{EXAMINE} uses a different algorithm to determine bin sizes.} Histograms are not created for string variables. Specify @subcmd{NORMAL} to superimpose a normal curve on the @@ -209,12 +212,26 @@ histogram. The @subcmd{PIECHART} subcommand adds a pie chart for each variable to the data. Each slice represents one value, with the size of the slice proportional to the value's frequency. By default, all non-missing values are given -slices. The @subcmd{MINIMUM} and @subcmd{MAXIMUM} keywords can be used to limit the -displayed slices to a given range of values. The @subcmd{MISSING} keyword adds -slices for missing values. - -The @subcmd{FREQ} and @subcmd{PERCENT} options on @subcmd{HISTOGRAM} and @subcmd{PIECHART} are accepted -but not currently honoured. +slices. +The @subcmd{MINIMUM} and @subcmd{MAXIMUM} keywords can be used to limit the +displayed slices to a given range of values. +The keyword @subcmd{NOMISSING} causes missing values to be omitted from the +piechart. This is the default. +If instead, @subcmd{MISSING} is specified, then a single slice +will be included representing all system missing and user-missing cases. + +@cindex bar chart +The @subcmd{BARCHART} subcommand produces a bar chart for each variable. +The @subcmd{MINIMUM} and @subcmd{MAXIMUM} keywords can be used to omit +categories whose counts which lie outside the specified limits. +The @subcmd{FREQ} option (default) causes the ordinate to display the frequency +of each category, whereas the @subcmd{PERCENT} option will display relative +percentages. + +The @subcmd{FREQ} and @subcmd{PERCENT} options on @subcmd{HISTOGRAM} and +@subcmd{PIECHART} are accepted but not currently honoured. + +The @subcmd{ORDER} subcommand is accepted but ignored. @node EXAMINE @section EXAMINE @@ -294,10 +311,9 @@ The first three can be used to visualise how closely each cell conforms to a normal distribution, whilst the spread vs.@: level plot can be useful to visualise how the variance of differs between factors. Boxplots will also show you the outliers and extreme values. - -@subcmd{HISTOGRAM} uses Sturges' rule to determine the number of -bins, as approximately 1 + log2(n). (Note that @cmd{FREQUENCIES} uses a -different algorithm to find the bin size.) +@footnote{@subcmd{HISTOGRAM} uses Sturges' rule to determine the number of +bins, as approximately @math{1 + \log2(n)}, where @math{n} is the number of samples. +Note that @cmd{FREQUENCIES} uses a different algorithm to find the bin size.} The @subcmd{SPREADLEVEL} plot displays the interquartile range versus the median. It takes an optional parameter @var{t}, which specifies how the data @@ -514,6 +530,7 @@ CROSSTABS ASRESIDUAL,ALL,NONE@} /STATISTICS=@{CHISQ,PHI,CC,LAMBDA,UC,BTAU,CTAU,RISK,GAMMA,D, KAPPA,ETA,CORR,ALL,NONE@} + /BARCHART (Integer mode.) /VARIABLES=@var{var_list} (@var{low},@var{high})@dots{} @@ -656,8 +673,15 @@ some statistics are calculated only in integer mode. @samp{/STATISTICS} without any settings selects CHISQ. If the @subcmd{STATISTICS} subcommand is not given, no statistics are calculated. +@cindex bar chart +The @samp{/BARCHART} subcommand produces a clustered bar chart for the first two +variables on each table. +If a table has more than two variables, the counts for the third and subsequent levels +will be aggregated and the chart will be produces as if there were only two variables. + + @strong{Please note:} Currently the implementation of @cmd{CROSSTABS} has the -following bugs: +following limitations: @itemize @bullet @item @@ -685,6 +709,8 @@ FACTOR VARIABLES=@var{var_list} [ /METHOD = @{CORRELATION, COVARIANCE@} ] + [ /ANALYSIS=@var{var_list} ] + [ /EXTRACTION=@{PC, PAF@}] [ /ROTATION=@{VARIMAX, EQUAMAX, QUARTIMAX, PROMAX[(@var{k})], NOROTATE@}] @@ -703,7 +729,10 @@ FACTOR VARIABLES=@var{var_list} The @cmd{FACTOR} command performs Factor Analysis or Principal Axis Factoring on a dataset. It may be used to find common factors in the data or for data reduction purposes. -The @subcmd{VARIABLES} subcommand is required. It lists the variables which are to partake in the analysis. +The @subcmd{VARIABLES} subcommand is required. It lists the variables +which are to partake in the analysis. (The @subcmd{ANALYSIS} +subcommand may optionally further limit the variables that +participate; it is not useful and implemented only for compatibility.) The @subcmd{/EXTRACTION} subcommand is used to specify the way in which factors (components) are extracted from the data. If @subcmd{PC} is specified, then Principal Components Analysis is used.