homework 6

Is the following statement true or false? We can not legitimately conduct an independent-samples t test if the sample sizes of our two groups are different.

False

Which of the following is an assumption of the independent-samples t test, but not an assumption fo the one-sample t test?

Homogeneity of variance

Imagine that researchers appropriately conduct a paired-samples t test with 25 pairs of related scores. The mean difference between those 25 pairs of scores was 5.00. The standard deviation for the 25 difference scores was 7.50. What is the corresponding value for Cohen's d (rounded to three decimal places)? When computing your answer, please assume that the researchers are using a standard null hypothesis that predicts no differences.

0.667

Imagine that researchers appropriately conduct a paired-samples t test with 25 pairs of related scores. The mean difference between those 25 pairs of scores was 5.00. the standard deviation for the 25 difference scores was 7.50. Which of the following is the appropriate 95% confidence interval for these data (when reporting three decimal places)?

[1.904, 8.096]

Please consider the following data set. The initial row provides labels for two variables (i.e., X1 and X2). Each subsequent row represents a pair of related scores from the same person at two different points in time. X1 X2 2 4 6 7 7 6 3 5 8 9 Compute the appropriate t statistic to test the null hypothesis that there is no difference between means. When computing the t statistic, please retain a minimum of four decimal places for all intermediate steps ( when relevant). For your final answer, please report the absolute value of the t statistic with a minimum of three decimal places.

1.826

Assume the blood pressures of 10 people were measured before and after sleeping for the night. What is the corresponding critical t-value for a one-tailed, paired-samples t test with an alpha level of 0.05 (5%). Please report your answer as an absolute value and include three decimal places.

1.833

Imagine that a researcher appropriately conducts a two-tailed, independent- samples t test with an alpha level of 0.05 (5%). The first group has degrees of freedom equal to 19. the second group has degrees of freedom equal to 21. What is the critical value (as a t statistic) that would cut off the upper 2.5% of the corresponding sampling distribution. Please provide three decimal places when reporting your answer.

2.021

Imagine that a researcher conducts an experiment using a within-groups design. Specifically, the same participants provide related scores on a dependent variable at two different levels of an independent variable. (Please assume that a relevant population standard deviation is not known). Which of the following analyses would be appropriate for comparing means for both levels of the independent variable?

A paired-samples t test

Which of the following sampling distributions is used when conducting a paired-samples t test?

A sampling distribution of mean differences

Is the following statement true or false? If you appropriately compute a t statistic for 25 related pairs of scores (using JASP or a similar program), the t statistic will have the same absolute value as a correctly computed one-sample t statistic computed from the differences between those 25 pairs of related scores. Note: When answering, please assume that we have standard null hypotheses (indicating no differences) for two- tailed tests.

True