A pharmaceutical company conducted a study to test the effectiveness of its new antidepression medication. 500 adults suffering from depression were selected at random and were randomly assigned to either a treatment group or a placebo group. The experiment was double blind. The results were analyzed by the company. What, if any, problems with this study do you notice?

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?

You are a sales manager for a grocery store, and you want to see if the introduction of a new sales promotion will increase the sales in your store. To do so, you decided to create an experiment by giving a small sample of customers the promotion before expanding it to a larger customer base. You gave 18 people the promotion, and also observed the sales of 27 people who did not get the promotion as a control group. You found those who received the promotion to have an average monthly sales of $456.60, with a sample standard deviation of $52.23. You found those who did not receive the promotion had an average monthly sales of $361.46, with a sample standard deviation of $56.11. Suppose you want to use hypothesis testing (two-sample test) to investigate if the promotion has increased the sales of your store. Using the order promotion no promotion in your hypothesis test, what is the value of the test statistic for your analysis? Note: 1- Only round your final answer. Round your final…

st is 22. Oishi and Shigehiro (2010) report that people who move from home to home frequently as children tend to have lower than average levels of well-being as adults. To further examine this relationship, a psychologist obtains a sample of n = 12 young adults who each experienced 5 or more different homes before they were 16 years old. These participants were given a standardized well-being questionnaire for which the general population has a

Q1. Please answer fill-ins.

. A researcher suspects that the actual prevalence of generalized anxiety among children and adolescents is higher than the previously reported prevalence of generalized anxiety disorder among children and adolescents. The previously reported prevalence of generalized anxiety disorder among children and adolescents is 4.1%, and the researcher conducts a study to test the accuracy of the previously reported prevalence of generalized anxiety disorder by recruiting 98 children and adolescents from various pediatricians’ offices and tests them for generalized anxiety disorder using the DSM-5. The researcher determines that the prevalence of generalized anxiety disorder among the participants of the study is 6.8%. The researcher’s hypothesis, for a level of significance of 5%, should resemble which of the following sets of hypothesis? A) H0: p > .041; H1: p = .041; alpha= .05 B) H0: p > .041; H1: p = .041; alpha= .95 C) H0: p = .041; H1: p > .041; alpha= .05 D) H0: p = .041; H1: p…

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.

A group of 600 patients who suffer from seasonal allergies is asked to participate in a study to determine the effectiveness of a new medication. The patients are divided randomly into two groups, one was given the actual medication and one received a placebo pill. After 2 months of treatment, 64% of the patients who took the medication had fewer allergy symptoms, while only 36% of those who took the placebo had fewer allergy symptoms. a. What is the treatment variable? b. What is the response (or outcome) variable? c. Was this an observational study or a controlled experiment? Explain how you know. d. Assuming the rest of the study was well-designed, use your answers to discuss whether it would be reasonable to conclude that taking the new medication caused fewer allergy symptoms.

In 1972, half of a group of 111 low-income children from Chapel Hill, NC were randomly chosen for enrollment in an intensive pre-school program, while the other half were not enrolled in any preschool program.  30 years later the preschool group had a higher % attending college, higher average GPA for those who did attend college, and higher average wages than the non-preschool group.   Fill in the following table.   Is there a control treatment (and, if so, what is it)?   Is there any accounting for individual variation?   Is there repetition in the experiment?   Is the experiment reproducible?     Can we say with some confidence that preschool has some lasting effects on career outcomes?