soln4301

# soln4301 - Stat 430/830 Solutions 1 Solutions for#1 2 and 3...

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Stat 430/830 Solutions 1 Solutions for #1, 2 and 3 are in soln4301.doc, as well as computer output and plots for #4 and 5. 4. a) From the dot plot of the data we see that the duration is very slightly skewed to the right for the queens. There are not enough workers to say much about their distribution other than the durations are spread out more so that the data for the queens. The workers do have more higher durations than the queens, although whether this is significant or not will need to be tested. More worker data really should have been collected. 0Q W b) H : the population average duration is the same for the queens and the workers OR : = : a H : the population average duration is different for the queens and the workers QW OR : ± : where : represents the population average duration for the queens and : represents that for the workers. c) Note: the following comment about Levene’s test is NOT required. Levene’s test for equal variances indicates that the population variances are not equal (P-value < 0.0001). (Note, for testing for differences in variances, Levene’s test is preferred to Bartlett’s since the latter is not robust to non-normality. As I have mentioned in class, plots of the data/residuals, however, are better ways of checking for non-constant variance.) The two t-tests, one assuming equal variances and the other assuming unequal variances, give different results if an of " of 0.01 is used. That assuming equal variances strongly (P-value < 0.0001) indicates that the workers spend more time at the sources of pollination while the t-test assuming unequal variances gives only borderline evidence (P-value = 0.014). Given the evidence that the population variabilities

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soln4301 - Stat 430/830 Solutions 1 Solutions for#1 2 and 3...

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