X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=doc%2Fstatistics.texi;h=1e24c173516bcfa62ebb8d8af0ad432e3d1d9a34;hb=5ce0aa4323a1caafd709713671bae889e8410057;hp=9cc49557ea2ff288b4abd32e57580bc1f68ae115;hpb=af3d2be249020c55e0e90925ff3b21fc70501bac;p=pspp diff --git a/doc/statistics.texi b/doc/statistics.texi index 9cc49557ea..1e24c17351 100644 --- a/doc/statistics.texi +++ b/doc/statistics.texi @@ -136,9 +136,12 @@ FREQUENCIES [@{FREQ[(@var{y_max})],PERCENT[(@var{y_max})]@}] [@{NONORMAL,NORMAL@}] /PIECHART=[MINIMUM(@var{x_min})] [MAXIMUM(@var{x_max})] [@{FREQ,PERCENT@}] [@{NOMISSING,MISSING@}] + /BARCHART=[MINIMUM(@var{x_min})] [MAXIMUM(@var{x_max})] + [@{FREQ,PERCENT@}] + /ORDER=@{ANALYSIS,VARIABLE@} + (These options are not currently implemented.) - /BARCHART=@dots{} /HBAR=@dots{} /GROUPED=@dots{} @end display @@ -146,9 +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. @@ -195,9 +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 @@ -207,12 +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 @@ -255,7 +274,7 @@ factors which tell @pspp{} how to break down the analysis for each dependent variable. Following the dependent variables, factors may be specified. -The factors (if desired) should be preceeded by a single @subcmd{BY} keyword. +The factors (if desired) should be preceded by a single @subcmd{BY} keyword. The format for each factor is @display @var{factorvar} [BY @var{subfactorvar}]. @@ -292,10 +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 @@ -318,10 +336,10 @@ If the @subcmd{/COMPARE} subcommand is omitted, then @pspp{} behaves as if The @subcmd{ID} subcommand is relevant only if @subcmd{/PLOT=BOXPLOT} or @subcmd{/STATISTICS=EXTREME} has been given. -If given, it shoule provide the name of a variable which is to be used +If given, it should provide the name of a variable which is to be used to labels extreme values and outliers. Numeric or string variables are permissible. -If the @subcmd{ID} subcommand is not given, then the casenumber will be used for +If the @subcmd{ID} subcommand is not given, then the case number will be used for labelling. The @subcmd{CINTERVAL} subcommand specifies the confidence interval to use in @@ -415,15 +433,16 @@ GRAPH /SCATTERPLOT = @var{height} WITH @var{weight} BY @var{gender}. @end example -This example will produce a scatterplot where height is plotted versus weight. Depending -on the value of the gender variable, the colour of the datapoint is different. With -this plot it is possible to analyze gender differences for height vs. weight relation. +This example will produce a scatterplot where @var{height} is plotted versus @var{weight}. Depending +on the value of the @var{gender} variable, the colour of the datapoint is different. With +this plot it is possible to analyze gender differences for @var{height} vs.@: @var{weight} relation. @cindex histogram The subcommand @subcmd{HISTOGRAM} produces a histogram. Only one variable is allowed for -the histogram plot. For an alternative method to produce histograms @pxref{EXAMINE}. The -following example produces a histogram plot for variable weigth. +the histogram plot. +For an alternative method to produce histograms @pxref{EXAMINE}. The +following example produces a histogram plot for the variable @var{weight}. @example GRAPH @@ -511,6 +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{} @@ -653,8 +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 @@ -682,9 +709,11 @@ FACTOR VARIABLES=@var{var_list} [ /METHOD = @{CORRELATION, COVARIANCE@} ] + [ /ANALYSIS=@var{var_list} ] + [ /EXTRACTION=@{PC, PAF@}] - [ /ROTATION=@{VARIMAX, EQUAMAX, QUARTIMAX, NOROTATE@}] + [ /ROTATION=@{VARIMAX, EQUAMAX, QUARTIMAX, PROMAX[(@var{k})], NOROTATE@}] [ /PRINT=[INITIAL] [EXTRACTION] [ROTATION] [UNIVARIATE] [CORRELATION] [COVARIANCE] [DET] [KMO] [SIG] [ALL] [DEFAULT] ] @@ -700,7 +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. @@ -708,9 +740,13 @@ If @subcmd{PAF} is specified, then Principal Axis Factoring is used. By default Principal Components Analysis will be used. The @subcmd{/ROTATION} subcommand is used to specify the method by which the extracted solution will be rotated. -Three methods are available: @subcmd{VARIMAX} (which is the default), @subcmd{EQUAMAX}, and @subcmd{QUARTIMAX}. -If don't want any rotation to be performed, the word @subcmd{NOROTATE} will prevent the command from performing any -rotation on the data. Oblique rotations are not supported. +Three orthogonal rotation methods are available: +@subcmd{VARIMAX} (which is the default), @subcmd{EQUAMAX}, and @subcmd{QUARTIMAX}. +There is one oblique rotation method, @i{viz}: @subcmd{PROMAX}. +Optionally you may enter the power of the promax rotation @var{k}, which must be enclosed in parentheses. +The default value of @var{k} is 5. +If you don't want any rotation to be performed, the word @subcmd{NOROTATE} will prevent the command from performing any +rotation on the data. The @subcmd{/METHOD} subcommand should be used to determine whether the covariance matrix or the correlation matrix of the data is to be analysed. By default, the correlation matrix is analysed. @@ -1133,7 +1169,7 @@ outside the specified range are excluded from the analysis. The @subcmd{/EXPECTED} subcommand specifies the expected values of each category. There must be exactly one non-zero expected value, for each observed -category, or the @subcmd{EQUAL} keywork must be specified. +category, or the @subcmd{EQUAL} keyword must be specified. You may use the notation @subcmd{@var{n}*@var{f}} to specify @var{n} consecutive expected categories all taking a frequency of @var{f}. The frequencies given are proportions, not absolute frequencies. The @@ -1384,7 +1420,7 @@ of variable preceding @code{WITH} against variable following The @subcmd{/WILCOXON} subcommand tests for differences between medians of the variables listed. The test does not make any assumptions about the variances of the samples. -It does however assume that the distribution is symetrical. +It does however assume that the distribution is symmetrical. If the @subcmd{WITH} keyword is omitted, then tests for all combinations of the listed variables are performed. @@ -1548,7 +1584,7 @@ The list of variables must be followed by the @subcmd{BY} keyword and the name of the independent (or factor) variable. You can use the @subcmd{STATISTICS} subcommand to tell @pspp{} to display -ancilliary information. The options accepted are: +ancillary information. The options accepted are: @itemize @item DESCRIPTIVES Displays descriptive statistics about the groups factored by the independent @@ -1720,7 +1756,7 @@ RELIABILITY @end display @cindex Cronbach's Alpha -The @cmd{RELIABILTY} command performs reliability analysis on the data. +The @cmd{RELIABILITY} command performs reliability analysis on the data. The @subcmd{VARIABLES} subcommand is required. It determines the set of variables upon which analysis is to be performed.