1. G*power For Mac Catalina
2. G*power For Mac
3. G Power 3 Download
4. G Power software, free download For Mac
5. G-power Sample Size Calculator

G*Power is a tool to compute statistical power analyses for many different t tests, F tests, χ2 tests, z tests and some exact tests. G*Power can also be used to compute effect sizes and to display graphically the results of power analyses.

Some of G.Power for Mac aliases include 'GPower'. The application relates to Education Tools. The most popular version of the tool is 3.1. This application's bundle is identified as gpower. New in G.Power 3.1.9.2: Fixed a bug that could occur under very specific circumstances when transferring an effect size from the effect size drawer to the main window.

Whenever we find a problem with G*Power we provide an update as quickly as we can. We will inform you about updates if you click here and add your e-mail address to our mailing list. We will only use your e-mail address to inform you about updates. We will not use your e-mail address for other purposes. We will not give your e-mail address to anyone else. You can withdraw your e-mail address from the mailing list at any time.

Download the Short Tutorial of G*Power (PDF) written for G*Power 2 but still useful as an introduction

For more help, see the papers about G*Power in the References section below.

If you use G*Power for your research, then we would appreciate your including one or both of the following references (depending on what is appropriate) to the program in the papers in which you publish your results:

Faul, F., Erdfelder, E., Lang, A.-G., & Buchner, A. (2007). G*Power 3: A flexible statistical power analysis program for the social, behavioral, and biomedical sciences. Behavior Research Methods, 39, 175-191. Download PDF

Faul, F., Erdfelder, E., Buchner, A., & Lang, A.-G. (2009). Statistical power analyses using G*Power 3.1: Tests for correlation and regression analyses. Behavior Research Methods, 41, 1149-1160. Download PDF

To report possible bugs, difficulties in program handling, and suggestions for future versions of G*Power please send us an e-mail.

By downloading G*Power you agree to these terms of use:

1. G*Power is free for everyone. Commercial distribution is strictly prohibited.
2. G*Power is distributed from this website. If you wish to distribute G*Power in some other way, then you need to seek permission from the authors. Please send us an e-mail in which you specify how and for what purpose you intend to distribute G*Power.
3. You may use screenshots of G*Power without asking for permission.
4. Considerable effort has been put into program development and evaluation, but there is no warranty whatsoever.

Download G*Power 3.1.9.7 for Windows XP, Vista, 7, 8, and 10 (about 20 MB). Please make sure to choose “unpack with folders” in your unzip tool.

Download G*Power 3.1.9.6 for macOS 10.7 to 10.15 and 11 (about 2 MB).

17 March 2020 - Release 3.1.9.7

Windows

Changed the behavior of the “X-Y plot for a range of values” which allowed plotting graphs after changing input parameters in the main window without hitting the “Calculate” button which, however, is required to update the “X-Y plot for a range of values” with the new input parameters from the main dialog.

21 February 2020 - Release 3.1.9.6

Mac and Windows

Fixed a bug in z tests: Generic z test: Analysis: Criterion: Compute alpha: The critical z was calculated incorrectly.

Fixed a bug in t tests: Linear bivariate regression: One group, size of slope: |sy/sx| was sometimes calculated inccorrecty.

14 January 2020 - Release 3.1.9.5

Mac

Fixed a bug that caused the “Options” button (which is available for some tests in the main window) to disappear when “Hide distributions & control” was selected.

6 February 2019 - Release 3.1.9.4

Mac and Windows

Fixed a bug in t tests: Linear bivariate regression: One group, size of slope. Negative effect directions, that is, slope|H1 < slope|H0, were not always handled correclty. Furthermore, the restriction (|slope| < |sy/sx|) on the effect size, which was previously ignored, is now checked.

7 July 2017 - Release 3.1.9.3

Mac

Fixed a bug that could cause crashes.

28 March 2014 - Release 3.1.9.2

Mac

Fixed a bug in the χ² tests: Goodness-of-fit tests: Contingency tables module which prevented the computed effect size from appearing in the effect size drawer.

Windows

Fixed a bug that could occur under very specific circumstances when transferring an effect size from the effect size drawer to the main window.

G*power For Mac Catalina

10 March 2014 - Release 3.1.9.1

Mac

Now includes the calculator that previously has been included only in the Windows version.

4 February 2014 - Release 3.1.9

Mac and Windows

Fixed a bug in the sign test’s sensitivity analysis which led to an offset of -0.5 in the reported effect size.
Changed the behaviour of all tests based on the binomial distribution. The upper and lower limits are now always within the range [0,n] instead of [-1,n+1]. This change may lead to alpha values larger than the requested alpha values, but now we have the advantage that the upper and lower limits correspond to actual decision boundaries. For instance, in a two-sided test H0 is rejected if, for the observed number x of successes, it holds that x <= lower limit or x >= upper limit. Note, however, that the change affects the results only when N is very small.

31 January 2014 - Release 3.1.8

Mac and Windows

Improvements in the logistic regression module: (1) improved numerical stability (in particular for lognormal distributed covariates); (2) additional validity checks for input parameters (this applies also to the poisson regression module); (3) in sensitivity analyses the handling of cases in which the power does not increase monotonically with effect size is improved: an additional Actual power output field has been added; a deviation of this actual power value from the one requested on the input side indicates such cases; it is recommended that you check how the power depends on the effect size in the plot window.

19 April 2013 - Release 3.1.7

Mac and Windows

Fixed a problem in the exact test of Proportions: Inequality, two independent groups (uncontional). The problem only occurred when p1 > p2.

18 Frebruary 2013 - Release 3.1.6

Mac and Windows

Fixed a problem in the sensitivity analysis of the logistic regression. The problem only occurred when p2 >= p1.

Mac

Fixed a problem in Fisher’s exact test.

12 September 2012 - Release 3.1.5.1

Mac

Fixed a problem with the effect size drawers of ANOVA: Fixed effects. The drawers now appear correctly after clicking on the Determine button.

20 August 2012 - Release 3.1.5

Mac and Windows

Fixed a problem in the test of equality of two variances. The problem did not occur when both sample sizes were identical.
Fixed a problem in calculating the effect size from variances in the repeated measures ANOVA.

3 July 2012 - Release 3.1.4

Mac and Windows

Added an options dialog to the repeated-measures ANOVA which allows a more flexible specification of effect sizes.
Fixed a problem in calculating the sample size for Fisher's exact test. The problem did not occur with post hoc analyses.

22 June 2011 - Release 3.1.3

Mac and Windows

Fixed a bug in the ANCOVA module. Changing the number of covariates now correctly leads to the appropriate change in the denominator degrees of freedom.

5 January 2010 - Release 3.1.2

Mac and Windows

Renamed the Repetitions parameter in repeated measures procedures to Number of measurements (Repetitions was misleading because it incorrectly suggested that the first measurement would not be counted).
Fixed a problem in the sensitivity analysis of the logistic regression procedure: There was an error if Odds ratio was chosen as the effect size. The problem did not occur when the effect size was specified in terms of Two probabilities.

Mac

The Window menu now contains the option to hide the distributions plot and the protocol section (Hide distributions & protocol menu item) so that G*Power can be accommodated to small screens. This option has been available for some time in the Windows version (see View menu).

16 December 2009 - Release 3.1

Mac

Added procedures to analyze the power of tests for single correlations based on the tetrachoric model, comparisons of dependent correlations, bivariate linear regression, multiple linear regression based on the random predictor model, logistic regression, and Poisson regression.

08 December 2009 - Release 3.1.1

Windows

Re-enabled options dialog for Correlation: Bivariate normal model.

29 June 2009 - Release 3.1

Windows

Added procedures to analyze the power of tests referring to single correlations based on the tetrachoric model, comparisons of dependent correlations, bivariate linear regression, multiple linear regression based on the random predictor model, logistic regression, and Poisson regression.

24 January 2008 - Release 3.0.10

Mac and Windows

Fixed a problem in the X-Y plot for a range of values for Generic F tests. The degrees of freedom were not properly set in the graph, leading to erroneous plot values.

22 January 2008 - Release 3.0.9

Mac

Eliminated the brushed metal look for better readability under Mac OS X 10.5.

Windows

Fixed some minor GUI problems (buttons had German titles; button in file dialog named “open” instead of “save”).
Fixed problems with distribution plots (plots were sometimes not appropriately clipped when copied or saved as metafile; drawing glitches with some very steep curves).
The file dialog shown when saving graphs or protocols now uses the user's home directory (myDocuments) as defaults directory.

10 October 2007 - Release 3.0.8

Mac and Windows

G*power For Mac

Fixed a serious bug in the CDF routine of the noncentral t distribution introduced in the bugfix release 3.0.7. Please update immediately if you installed version 3.0.7.

8 October 2007 - Release 3.0.7

Mac and Windows

Fixed a bug in the function calculating the CDF of the noncentral t-distribution that occasionally led to (obviously) wrong values when p was very close to 1. All power routines based on the t distribution were affected by this bug.

14 August 2007 - Release 3.0.6

Mac

Fixed a bug in the routine that draws the central and noncentral t distributions for two-tailed tests. When alpha was very small, this bug could cause G*Power to crash.

03 July 2007 - Release 3.0.5

Mac and Windows

Fixed a bug in the Power Plot (opened using the X-Y-plot for a range of values button) for F tests, MANOVA: Global effects and F Tests, MANOVA: Special effects and interactions. Sometimes some of the variables were not correctly set in the plot procedure which led to erroneous values in the graphs and the associated tables.

26 June 2007 - Release 3.0.4

Mac and Windows

Fixed a bug in the Power Plot (opened using the X-Y-plot for a range of values button) for F Tests, Multiple Regression: Special (R2 increase). The numerator df value was not always correctly determined in the plot procedure which led to erroneous values in the graphs and the associated tables.
Fixed some minor problems with t tests. G•Power now checkes for invalid null effect sizes in a priori analyses. The t distribution PDF routine is now more robust for very large degrees of freedom by explicitly using a normal approximation in these cases.
When the Power Plot window was first opened by pressing the X-Y plot for a range of values button, the default was to show 4 plots simultaneously. The default has been changed to 1 plot.
Corrected some parsing errors in the calculator (in the Mac version, this only concerns text input in normal input fields).
Corrected a label in the effect size drawer for ANOVA: Fixed effects, omnibus, one-way. In the From variance input mode, the Variance within group field was erroneously labeled Error variance.

Windows

Fixed a problem with moving the main window when the effect size drawer is open. Sometimes the mouse pointer appeared to be 'glued' to the window and the movement could not be stopped properly.

1 March 2007 - Release 3.0.3

Mac and Windows:

Fixed a bug in the X-Y plots for a range of values for F Tests, ANOVA: Fixed effects, special, main effects and interactions. The df1 value was not always correctly determined in the plot procedure which led to erroneous values in the plots.
Fixed the problem in the plot procedure that (due to rounding errors) the last point on the x-axis was sometimes not included in the plot.

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28 February 2007 - Release 3.0.2

Mac and Windows

Fixed a probem with tooltips for effect size conventions which were not always shown.

Windows

Added options mainly intended to make G*Power usable with low resolution displays (800 x 600 pixels)
The distribution/protocol view and the test/analysis selection view in the main window can be hidden temporarily to save space. To hide/show these sub-views press F4 (plot/protocol) and F5 (test/analysis), respectively, while the main window is active. There are also corresponding entries in the View menu.
The Graph window can now be made resizable. To do this choose 'Resizable Window' in the View menu of the Graph window. Besides enabling (restricted) resizability this option initially shrinks the window to a size that fits into a 800 x 600 screen. Deselecting the option restores the Graph window to the fixed size for which G*Power was optimized.

Mac

Fixed a cosmetic problem when drawing “extreme” central and non-central distributions.

15 January 2007 - Release 3.0.1

Windows

Effect size calculation for t Tests, Difference between two indepent means (two groups), case n1 = n2: The wrong means—those of case n1 ≠ n2—were used to calcultate the effect size. This problem has been fixed.
Minor cosmetic changes.
New Readme file.
Updated installation instruction.

12.01.2007 - First release of version 3.0.0

Axel Buchner, Edgar Erdfelder, Franz Faul, Albert-Georg Lang

The Power Mac G4 is a series of personal computers designed, manufactured, and sold by Apple Computer, Inc. from 1999 to 2004 as part of the Power Macintosh line. Built around the PowerPC G4 series of microprocessors, the Power Mac G4 was marketed by Apple as the first 'personal supercomputers',^[1] reaching speeds of 4 to 20 gigaFLOPS. This was the first existing Macintosh product to be officially shortened as 'Mac', and is the last Mac able to boot into classic Mac OS.

The enclosure style introduced with the Power Macintosh G3 (Blue and White) was retained through the entire five-year production run of the Power Mac G4, albeit with significant changes to match Apple's evolving industrial design and to accommodate increasing cooling needs. The G4 and its enclosure were retired with the introduction of the Power Mac G5.

PCI Graphics/AGP Graphics/Gigabit Ethernet[edit]

The original Power Mac G4 was introduced at the Seybold conference in San Francisco on August 31, 1999.^[2] There were two variants, officially titled Power Mac G4 (AGP Graphics) with 400 MHz, 450 MHz and 500 MHz configurations available, and Power Mac G4 (PCI Graphics), with 350 MHz and 400 MHz configurations. Colloquially, this generation of Power Mac is referred to as 'Graphite', owing to the colors of the case being similar to the iMac G3 Graphite.

Apple originally planned to ship the 500 MHz configuration in October 1999, but they were forced to postpone this because of poor yield of the CPUs. In response, Apple reduced the clock speed of the processor in each configuration by 50 MHz (making the options 350 MHz, 400 MHz and 450 MHz), which caused some controversy because they did not lower the original prices accordingly.^[3]

The early 400 MHz (later 350 MHz) PCI-based version used a motherboard identical to the one used in Power Macintosh G3 (Blue and White) computers including the use of Zero Insertion Force (ZIF) processors sockets^[4] (minus the ADB port), in a 'graphite' colored case and with the new MotorolaPowerPC 7400 (G4) CPU. The higher-speed models, code name 'Sawtooth', used a greatly modified motherboard design with AGP 2x graphics (replacing the 66 MHz PCI slot).

The PCI variant was discontinued at the end of 1999.^[5]

The machines featured DVD-ROM drives as standard. The 400 MHz and 450 MHz versions had 100 MBZip drives as standard equipment, and as an option on the 350 MHz Sawtooth. This series had a 100 MHzsystem bus and four PC100SDRAM slots for up to 2 GB of RAM (1.5 GB under Mac OS 9). The AGP Power Macs were the first to include an AirPort slot and DVI video port. The computers could house a total of three hard drives, two 128 GB ATA hard drives and up to a single 20GB SCSI hard drive, with the installation of a SCSI card.

The 500 MHz version was reintroduced on February 16, 2000, accompanied by 400 MHz and 450 MHz models. DVD-RAM and Zip drives featured on these later 450 MHz and 500 MHz versions and were an option on the 400 MHz.

The Power Mac G4 (Gigabit Ethernet) model was introduced at Macworld ExpoNew York on July 19, 2000; the new revision included dual-processor 450 MHz and 500 MHz versions, and a low-end single CPU 400 MHz model. It was also the first personal computer to include gigabit Ethernet as standard. Most people saw this revision as a stopgap release, because higher clocked G4s were not available; the G4’s Motorola XPC107 “Grackle” PCI/Memory controller prevented the G4 from hitting speeds higher than 500 MHz.^{[citation needed]} The dual 500 MHz models featured DVD-RAM optical drives. Zip drives were optional on all models. These models also introduced Apple's proprietary Apple Display Connector video port.

Digital Audio/Quicksilver[edit]

A new line with a revamped motherboard but retaining the familiar 'Graphite' case debuted on January 9, 2001. Known officially as the Power Mac G4 (Digital Audio), it is in effect a Quicksilver design inside the Graphite enclosure. Motorola had added a seventh pipeline stage in the new PowerPC G4 design to achieve faster clock frequencies. New features included a fourth PCI slot, a 133 MHz system bus, an improved 4X AGP slot, and a new 'digital audio' Tripath Class T amplifier sound system. The models were offered in 466 MHz, 533 MHz, dual 533 MHz, 667 MHz and 733 MHz configurations, the latter two using a newer PowerPC 7450 processor. The number of RAM slots was reduced to three, accommodating up to 1.5 Gigabytes of PC133SDRAM.

The 733 MHz model was the first Macintosh to include a built-in DVD-R or Apple-branded SuperDrive, the rest of the line became the first Macs to ship with CD-RW drives. This was also the first series of Macs to include an Nvidia graphics card, the GeForce 2MX.

At Macworld ExpoNew York on July 18, 2001, a new line debuted featuring a cosmetically redesigned case known as Quicksilver, and various upgrades to the specifications. It was available in 733 MHz, 867 MHz and dual 800 MHz configurations. The 733 MHz model was notable for not having a level three cache. The SuperDrive was offered on the mid-range 867 MHz model, and UltraATA/100 hard drives were offered on all models. The internal speaker received an upgrade, using a Harman/Kardon speaker.

The Quicksilver line received criticism in MacWorld's review for removing the 'eject' button and the manual eject pinhole, as well as the pass-through monitor power plug, and for the base specification of 128 MB RAM as being insufficient for running Mac OS X.^[6]

Updated Quicksilver machines, officially named Power Mac G4 (QuickSilver 2002), were introduced on January 28, 2002, with 800 MHz, 933 MHz and dual 1 GHz configurations. This was the first Mac to reach 1 GHz. Again, the low-end 800 MHz model did not include any level three cache. The graphics in this series were provided by an Nvidia GeForce4 MX400 card. Some of these models have ATA controllers with 48-bit LBA to accommodate hard drives larger than 128 GB.

Mirrored Drive Doors/FW800[edit]

Another generation of Apple Power Mac G4s, officially named 'Mirrored Drive Doors' (MDD), was introduced on August 13, 2002, featuring both a new Xserve-derived DDR motherboard architecture and a new case design. All models were available in dual processor configurations running at 867 MHz, 1 GHz or 1.25 GHz. As with the Xserves, the PowerPC 7455 CPU used does not have a DDR frontside bus, meaning the CPU could use at most only 50% of the new system's theoretical memory bandwidth, providing no improvement over previous models. The rest was available to the graphics card and I/O systems. A single processor 1.25 GHz model would be the last Power Mac G4 the company offered to the public after the announcement of the new Power Mac G5, introduced in June 2003.

The last real update to the Power Mac G4 line came on January 28, 2003, offering dual 1.42 GHz PowerPC 7455 processors, with features not seen in previous DDR models: a built-in FireWire 800 connector, optional integrated Bluetooth, and optional integrated AirPort Extreme. These were also the first Power Macs that could not boot into Mac OS 9.

With the launch of the Power Mac G5 on June 23, 2003, Apple re-introduced the August 2002 Power Mac G4 because of perceived demand for Mac OS 9 machines. Between that, its low price-tag, and the delayed availability of Power Mac G5s, it proved a strong seller, albeit for a relatively short time. Production stopped on June 27, 2004, and the remaining inventory was liquidated, its discontinuation ending the 20-year legacy of Classic Mac OS support.

Timeline of Power Macintosh models

G Power software, free download For Mac

See also[edit]

Notes[edit]

1. ^'Apple Unveils 'Personal Supercomputer''. SFGate.
2. ^'Apple steps up to G4 Macs'. ZDNet.
3. ^'The 400 MHz PowerMac Reviewed'. The Mac Observer. February 21, 2000. Retrieved October 19, 2008.
4. ^'The Apple Power Macintosh G4 400MHz PCI'. Forevermac.com. Retrieved November 30, 2011.
5. ^'Power Mac G4 (PCI Graphics) - Technical Specifications'.
6. ^'Hands on with the Power Mac G4/867'. MacWorld. August 25, 2001.

G-power Sample Size Calculator