Exam 10: Comparing Two Means

Examine the following SPSS output from the heart rate data. Based on 11 degrees of freedom, working to a two-tailed significance value of .05, the critical value for t is 2.201. What can you assume from the output? (The significance value has been omitted on purpose.)

Which of the following issues are likely to cause Type II error in the cancer survival data?

When analysing the cancer survival data, a p-value set at .05 or .01 is most likely to protect against which type of error?

When analysing the result of the paired samples t-test, the output presents the following box, but what do the results show you?

Which of the following expressions best represents the degrees of freedom?

If a significance result of .000 is presented, how should this be reported?

When exploring the data before performing a t-test, how might you wish to present the data graphically? (You may select more than one option.)

Run an independent t-test on the data. A Levene's test result of p = .006 was obtained. What can we infer from this number?

Assume that for the research into stomach and lung cancer the significance value is set at p < .05 and an independent t-test yielded a significance value of p = .06. What should you do?

Suppose we wanted to apply a one-tailed test as opposed to a two-tailed test. How would we covert a significance of p = .284?

When comparing pre-competition arousal scores in novice and expert tennis players you find that the scores for the novice group are not normally distributed. What test should be run to see if arousal scores are statistically different?

How is a t-statistic calculated?

According to Cohen, how might this effect size be interpreted?

Once you have the significance value of the t-test, it is beneficial to calculate the effect size. Cohen's d is a measure of effect size. How is it calculated?

Which of the following is not a form of t-test?

What does a negative t-statistic suggest?

Which of the following t-tests has a different research design?

How might you classify the measurement scale of the survival rate (days)?

Analyse the data below related to days survival following surgery from either stomach or lung cancer. What is the result of the Kolmogorov-Smirnov test for the patients who survived stomach cancer?

How might you classify the measurement scale for the variable labelled as cancer?