You can make horizontal images 1024 pixels wide and vertical images 768 pixels high, each using the maximum amount of space in 1024x768 black canvas (background color) template. For images that don’t fit that aspect ratio exactly, create a black canvas to fill in the empty space so the images are projected in a dark room-only the image will be seen. If you are not sure, use 1024x768 (at 72 ppi) in the sRGB color space. Both SVGA (800圆00) and XGA (1024x768) projectors are common, so it helps if you know in advance which one will be projecting your work.
Digital projectors, like monitors, only see actual pixels.
While you’re working with all these choice images for your web gallery you can easily create an additional folder of images optimized for a digital slide show presentation. Add Unsharp Mask to bring back the sharpness lost in re-sizing.ĥ. Re-size to the desired long dimension pixel size.Ģ. Review authors should look for evidence of which one, and might use a t distribution if in doubt.This tabbed interface changes with each “skin,” allowing features, layout and content to be specified before each album is generated.ġ. The divisor, 3.92, in the formula above would be replaced by 2 × 2.0639 = 4.128.įor moderate sample sizes (say between 60 and 100 in each group), either a t distribution or a standard normal distribution may have been used. For example the t value for a 95% confidence interval from a sample size of 25 can be obtained by typing = tinv(1-0.95,25-1) in a cell in a Microsoft Excel spreadsheet (the result is 2.0639). Relevant details of the t distribution are available as appendices of many statistical textbooks, or using standard computer spreadsheet packages. The numbers 3.92, 3.29 and 5.15 need to be replaced with slightly larger numbers specific to the t distribution, which can be obtained from tables of the t distribution with degrees of freedom equal to the group sample size minus 1.
If the sample size is small (say less than 60 in each group) then confidence intervals should have been calculated using a value from a t distribution. The standard deviation for each group is obtained by dividing the length of the confidence interval by 3.92, and then multiplying by the square root of the sample size:įor 90% confidence intervals 3.92 should be replaced by 3.29, and for 99% confidence intervals it should be replaced by 5.15. If the sample size is large (say bigger than 100 in each group), the 95% confidence interval is 3.92 standard errors wide (3.92 = 2 × 1.96). Most confidence intervals are 95% confidence intervals. Again, the following applies to confidence intervals for mean values calculated within an intervention group and not for estimates of differences between interventions (for these, see Section 7.7.3.3). When making this transformation, standard errors must be of means calculated from within an intervention group and not standard errors of the difference in means computed between intervention groups.Ĭonfidence intervals for means can also be used to calculate standard deviations. 7.7.3.2 Obtaining standard deviations from standard errors and confidence intervals for group meansĪ standard deviation can be obtained from the standard error of a mean by multiplying by the square root of the sample size: For the current version, please go to /handbook/current or search for this chapter here. This is an archived version of the Handbook.
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