You want to determine if chocolate enhances mood. Subjects will be recruited and randomly assigned to one of two groups: Those in the control group will eat their regular diet, and those in the experimental group will also eat their usual meals and have one piece of chocolate at breakfast, lunch, and dinner over the course of a week. At the end of the week, all subjects (in both groups) will complete the Acme Mood Scale (1 = extremely bad mood, 100 = extremely good mood). Data set: Ch 05 - Exercise 04A.sav Codebook Variable: group Definition: Chocolate dosage group assignment Type: Categorical (1 = No chocolate, 2 = Chocolate [1 per meal]) Variable: mood Definition: Score on Acme Mood Scale Type: Continuous (1 = extremely bad mood, 100 = extremely good mood) Write the hypotheses

Tim is interested in studying whether Cognitive Behavioural Therapy (CBT) is an effective treatment for Obsessive Compulsive Disorder (OCD). Six people who were diagnosed with OCD participated in Tim's study, where he recorded the number of times they washed their hands per day for one month. They were then given a three week intensive CBT program before their hand-washing was monitored for another month. The average number of times per day each participant washed their hands over the two months of observation are as follows: Participant Month 1 Month 2 1 11 6 2 8 5 3 14 17 4 10 10 5 22 11 6 15 10   Compute the appropriate statistic to determine whether the program was effective and use this information to fill in the blanks:   Q1. revealed that the number of times per day participants washed their hands following the CBT program was Q2. compared to the number of times per day participants washed their hands before the…

Below is data from a study examining the effects of two different psychotherapy treatments on self-esteem. Specifically, two different treatment types (treat1 and treat2) were compared to a waiting list control group in terms of increasing self-esteem; the main question concerned whether each separate therapy type was different from no treatment at all. The values shown below are the self-esteem scores for the participants in each group (higher values indicate greater self-esteem). a. What are the null and alternative hypotheses? b. If there are differences between the groups, be specific with respect to which groups differ

A food-frequency questionnaire is used to measure dietary intake. The respondent specifies the number of servings of various food items they consumed over the previous week. The dietary cholesterol is then quantified for each respondent. The researchers were interested in assessing if there was an association between dietary cholesterol intake and high blood pressure. In a large sample of individuals who had completed the questionnaire, 250 persons with a high dietary cholesterol intake (greater than 300 mg /day) were selected and 250 persons with a low dietary cholesterol intake (less than 300 mg/day) were selected. The 500 selected participants had their medical history taken and were classified as having normal or high blood pressure. The data are given here. Dietary Cholesterol Blood Pressure Total High Low High 159 91 250 Low 78 172 250 Total 237 263 500 Test 2: two-tailed test for comparing two independent proportions Clearly state…

Read the scenario below to determine which one of the time threats to internal validity (test reactivity, instrumentation, history, and maturation) is of most concern, and provide one way to control for the threat. A researcher examines students' perception of their body image by conducting a 2-year longitudinal study of middle-school students (grades 6 - 8).  Body image is measured using a scale and the same scale is measured under the same conditions at the beginning and end of the study.

A psychologist conducted a survey of the attitude towards the sustainability of American energy consumption with 250250 randomly selected individuals several years ago. The psychologist believes that these attitudes have changed over time. To test this he randomly selects 250250 individuals and asks them the same questions. Can the psychologist confirm his theory that the attitudes have changed from the first survey to the second survey? Attitude 1st Survey 2nd Survey Optimistic 50%50% 52%52% Slightly Optimistic 16%16% 10%10% Slightly Pessimistic 11%11% 15%15% Pessimistic 23%23% 23%23% Copy Data Step 6 of 10 :   Find the value of the test statistic. Round your answer to three decimal places. Step 7 of 10: Find the degrees of freedom associated with the test statistic for this problem Step 8 of 10: Find the critical value of the test at the 0.025 level of significance. Round your answer to three decimal places.step 9 of 10: make the decision to reject or fail to reject…