A researcher was interested in how the effects of stress were different in people with our without military training. A equal number of participants were recruited that either had no military experience or had completed military experience. All participants were asked to give a speech without preparation while being judged by a panel of experts. Their heart rates were monitored during the speech and an average heart rate was calcuated for each participant. Which statistical test would be best to determine if there is a significant difference between groups? one-sample t-test dependent samples t-test independent samples t-test ANOVA

A graduate student is interested in how viewing different types of scenes affects working memory. For his study, he selects a random sample of 36 adults. The subjects complete a series of working memory tests before and after walking in an urban setting. Before the walk, the mean score on the test of working memory was 9.1. After the walk, the mean score was 1.4 higher. The graduate student has no presupposed assumptions about how viewing different types of scenes affects working memory, so he formulates the null and alternative hypotheses as: H00 : μDD = 0 H11 : μDD ≠ 0 Assume that the data satisfy all of the required assumptions for a repeated-measures t test. The graduate student calculates the following statistics for his hypothesis test: Mean difference (MDD) 1.4 Estimated population standard deviation of the differences (s) 1.6 Estimated standard error of the mean differences (sMDMD) 0.2667 Degrees of freedom (df) 35 The t statistic 5.25 The critical values of t…

A researcher gathered a sample of participants who volunteered for a studying of phobias. She measured anxiety level of participants as they viewed photos of spiders and again when they viewed puppies. Which statistical test is appropriate for this study and why?

Researchers investigate how the presence of cell phones influence the quality of human interaction.  Subjects are randomly selected from a population and divided into an experimental group that is asked to leave their phones in the front of the room and a control group that are not asked to leave their cell phones at the front of the room.  Subjects are left alone for 10 minutes and then asked to take a survey designed to measure quality of interactions they had with others in the experiment.  What statistical test is appropriate?

At BYU-Idaho there has been a lot of interest in the performance of students in online classes. Generally, administrators are interested to know if there is a difference in the learning of students who take an online course compared to those who take a traditional course. A study was done to see if the grade received in the course is related to the type of course. Researchers collected the grades of randomly selected students who were taking a traditional Business Statistics class and compared those with the grades earned by randomly selected students who were taking an online Business Statistics class. The data are shown in the table below. Grade A B с D F You want to determine if a student's grade and the type of course he or she is enrolled in are independent. Use a level of significance of a = 0.01. State the null and alternative hypothesis for this test. O Ho: Traditional and online courses are not independent. H₂: Traditional and online courses are independent. O Ho: Traditional…

Do you think the results of the study might be applicable to the whole population? Why or why not?

Acne is a common skin disease that affects most adolescents and can continue into adulthood. A study compared the effectiveness of three acne treatments and a placebo, all in gel form, applied twice daily for 12 weeks. The study's 517 teenage volunteers were randomly assigned to one of the four treatments. Success was assessed as clear or almost clear skin at the end of the 12 week period. The results of the study can be seen in the table below. Using the appropriate statistical test, determine if there is significant evidence that the four treatments perform differently. If so, how do they compare.

Anterior cruciate ligament (ACL) injuries occur most frequently in planting and cutting sports such aa basketball, soccer, and volleyball. A sports medicine researcher wants to test if female athletes are more likely to have an ACL injury than males. He surveyed 50 collegiate programs that had both men's and woman's volleyball and asked them how many grade 3 ACL tears they had during the past season. Which statistical test would be best to determine if there is a significant diffence between groups? One sample t test  Dependent samples t test Independent samples t test ANOVA

Computer-mediated communication (CMC) is a form of interaction that heavily involves technology (e.g., instant messaging, email). A study was conducted to compare relational intimacy in people interacting via CMC to people meeting face-to-face (FTF).   Participants were 48 undergraduate students, of which half were randomly assigned to the CMC group and half assigned to the FTF group. The variable of interest, relational intimacy score, was measured (on a 7-point scale) for each participant after each of three different meeting sessions. Summary statistics for the first meeting session are given here. The researchers hypothesized that, after the first meeting, the mean relational intimacy score for participants in the CMC group would be lower than the mean relational intimacy score for participants in the FTF group. Test the researchers’ hypothesis using α = .10.                                                                     CMC                                           FTF Number…

Researchers asked soda drinkers to view either the logo for their favorite soda or a graphic warning demonstrating the harmful effects of sugary beverages (e.g., tooth decay, obesity) and then measured their negative mood with a short survey. They found that those participants who saw the warnings reported significantly greater negative moods than those who saw the logos. Which statistical test should be used?