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Do college students preform worse in online courses? To answer this question, a researcher compared the test scores of students enrolled in online vs. in person class. Their scores are presented in a table below. Using a one-tailed test with α = .05, what conclusion should be made? 

What do you do when the homogeneity of variance assumption is violated in a t-test?

Which of the following confidence intervals (i.e., 1, 2, 3, and 4) indicate a significant mean difference between two groups? Please explain how you know.

State the null and the alternative hypotheses using symbols. 

Suppose a researcher wants to decrease the width of the confidence interval. What are two ways in which this can be accomplished?

Compute Cohen’s d to measure the size of the effect in the study in Q20. d = [color1]

The pooled variance will be closer to whichever variance is larger, regardless of the sample sizes.

Far zone beam divergence can be reduced on a single element transducer by using

A sound beam is shaped like a ____________________

The diameter of a transducer is 12 mm.  The near zone length is 8 mm.  The focal zone is 4 mm.  What is the diameter of the sound beam at 8 mm?