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A student investigated how washing with soap affects bacteria levels on the hands. She tested three different methods—washing with water only, washing with regular soap, and washing with antibacterial soap. She randomly assigned 99 students to one of the 3 treatments. Participants washed their hands with the assigned method and cultures were taken and incubated. Based on the SPSS output below, was there a significant difference among the three hand-washing methods and why?

Which combination of factors is most likely to produce a significant value for an independent-measures t statistic?

Which combination of factors is most likely to produce a significant value for an independent-measures t statistic?

One sample has a variance of s2 = 10 and a second sample has a variance of s2 = 6.  If the two samples have the same number of scores, what is the pooled variance for the two samples?

A sample has M = 72 and s = 4.  In this sample, what is the X value corresponding to z = –2.00?

One sample has a variance of s2 = 10 and a second sample has a variance of s2 = 6.  If the two samples have the same number of scores, what is the pooled variance for the two samples?

In analysis of variance, what is a factor?

An independent-measures study comparing two treatment conditions produces a t statistic with df = 18.  If the two samples are the same size (n1 = n2), how many participants were in each of the samples?

A two-factor research study has two levels of factor A and three levels of factor B with 8 participants in each treatment condition.  For this study, what is the value for dfbetween treatments?

Using letter grades (A, B, C, D, and F) to classify student performance on an exam is an example of measurement on a(n) ____ scale of measurement.