Exam 14: Strategies When Population Distributions Are Not Normal: Data Transformations and Rank-Order Tests

A sports psychologist was interested in whether imagery would change the performance of five bowlers.Performance was assessed when bowling in a normal manner and when bowling with imagery instructions (i.e.,concentrate on pleasant settings for 10 seconds before each turn); order of conditions was randomized.The scores were as follows: a.Conduct a t test for dependent means with the original difference scores using the .01 level. b.Apply a square root transformation to the difference scores,and then conduct another t test with these transformed scores. c.Explain the reasons for using the transformation and the implications of the difference in results of these two methods.Write your explanation for a person who is familiar with the t test for dependent means,but not with data transformations.

When the assumption of a normal curve is seriously violated,the ordinary t test

A researcher wants to compare attitudes towards fraternities at two different colleges using a t test for independent means.The scores for five randomly selected students at College A were 1,9,16,25,and 49.The scores for five randomly selected students at College B were 9,25,36,49,and 81. -The t score calculated for the t test for independent means is __________.

When conducting a statistical test,a single outlier can

Describe the distributions of the following scores: a.101,120,131,143,146,2902 b.-109,-0.9,-0.1,-0.1,0,0.3,0.4

Having discovered an extreme score in a sample of scores,the first thing to do is to

Which of the following is a nonparametric test?

In a square-root transformation,

When a distribution is negatively skewed,which of the following transformations should be performed first?

The rank-order test that would be used in the same kind of research situation as an analysis of variance is

A researcher wants to compare attitudes towards fraternities at two different colleges using a t test for independent means.The scores for five randomly selected students at College A were 1,9,16,25,and 49.The scores for five randomly selected students at College B were 9,25,36,49,and 81. -Given that the critical value (.05 level,two-tailed)is __________,the researcher's decision should be __________.

Procedures that allow one to analyze scores from nonnormal samples using the standard parametric procedures such as t tests and analyses of variance are __________.

A researcher wants to compare attitudes towards fraternities at two different colleges using a t test for independent means.The scores for five randomly selected students at College A were 1,9,16,25,and 49.The scores for five randomly selected students at College B were 9,25,36,49,and 81. -For College B's transformed scores,the mean is __________,and the standard deviation is __________.

If a research article included a statement that "level of intensity was compared to reaction time using a Wilcoxon rank-sum test," the statistical test was a(n)__________ test.

The rank-order test that would be used in the same kind of research situation as a t test for dependent means is

A researcher wants to compare attitudes towards fraternities at two different colleges using a t test for independent means.The scores for five randomly selected students at College A were 1,9,16,25,and 49.The scores for five randomly selected students at College B were 9,25,36,49,and 81. -The standard deviation of the comparison distribution (S_difference)is __________.

A widely used procedure when the sample's scores do not appear to come from a normal population is to

Prior to using a procedure that is "distribution-free," the sample scores would probably be transformed using the

A nonparametric version of the t test for independent means is the __________ test.

For the scores 12,13,14,15,16,and 17,the shape of the distribution is __________.