A study examined the impact of THC, the active ingredient in marijuana, on various physiological and psychologicalvariables. The study recruited a sample of 18 young adults who were habitual marijuana smokers. Participants came to thelab 3 times, each time completing the entire series of tests and questionnaire, but each time smoking a different marijuanacigarette: one with 3.9% THC, one with 1.8% THC, and one with no THC, a placebo. The order of the conditions wasrandomized and participants were not told how much THC was in the cigarette they smoked until after all the data werecollected. This is an example ofa completely randomized experiment.O a case-control observational study.an anecdotal evidence.O a matched pairs or repeated measures experiment.Incorrect

Answered: Image /qna-images/answer/f68fe4c8-54e3-46a8-954a-9efaaafce746.jpg

Answered: A study examined the impact of THC, the…

MATLAB: An Introduction with Applications

6th Edition

ISBN:9781119256830

Author:Amos Gilat

Publisher:Amos Gilat

Chapter1: Starting With Matlab

Section: Chapter Questions

Problem 1P

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A sports psychologist studied the effect of a motivational program on number of injuries in one year among players of three different sports (baseball, football, and basketball). Players were randomly assigned to one of two conditions: either participate in a motivational program or none (control). Data was collected on the number of injuries sustained by each athlete that season. Question: If p = .024 for the main effect of sports, what should the researcher conclude?
You are testing to see if p1 = .2, p2 = .3 and p3 = .5. You take a sample of size 100 and tind 22 of the first population, 27 of the second population and 51 from the third population. Test Ho : P1 = .2, p2 = .3 and p3 = .5 against H1 : not Ho using alpha = .05.
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…
A researcher is interested in investigating the relationship between sugar consumption and weight gain for high school students. 15 volunteers were randomly assigned to one of two groups. The first group contained 6 volunteers who were put on a low sugar diet. The second group consisting of the remaining 9 volunteers was put on a diet with sugar constituting approximately 15% of their diet. After 8 weeks, the change in weight was recorded for each of the volunteers. Question: What is the response variable? What study principle was used in this study and what kind of study is this?
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…
A researcher believes that there may be a negative association between the quantity of fertilizer used and the percentage of the population who live in rural areas in different countries. The data below shows the percentage of the population who live in rural areas and the fertilizer use measured in kg per hectare, for a random sample of 11 countries. 33%= 76kg, 6%=44kg, 58%= 6kg, 35%=68kg, 81%=3kg, 69%=10kg, 61%=7kg, 7%=176kg,74%=5kg, 71%=137kg, 17%=157kg Use the Spearman's rank order coefficient method to affirm or disagree with the researchers assumption.
A researcher wants to conduct an experiment to determine which environment is best suited for studying - a library, in one's own room, or outside. A total of 30 university students volunteer to participate in the experiment. The researcher believes that gender has an effect on the results. What are the treatments in the experiment?
A recent study investigated whether cell phone users experience separation anxiety when they cannot access their phones. Because blood pressure increases with anxiety, the researchers used systolic blood pressure as an operational measure of anxiety. The experiment involved a random sample of cell phone users that were divided into two groups at random. One group of participants completed a survey while their phones were locked in a cabinet in a separate room and the other group of participants completed the same survey while their phones were nearby. (The survey questions were unrelated to cell phone use.) At the end of the survey, theresearchers measured each participant's systolic blood pressure. The same experiment was conducted in Montreal, Toronto, Vancouver, and St. Zotique. The blood pressure data for all participants needed are below. Use these data to answer the following question: comoute the estimated standard error of d for the data collected in toronto. Please answer to 5…
Find A= %b= %c= %d= %
Researchers suspect that drinking tea might enhance the production of interferon gamma, a molecule that helps the immune system fight bacteria, viruses, and tumors. A recent study involved 20 healthy people who did not normally drink tea or coffee. Ten of the participants were randomly assigned to drink five cups of tea a day, while 10 were asked to drink the same amount of coffee. After two weeks, blood samples were exposed to an antigen and production of interferon gamma were measured. The results are shown in the following table: Теа: 55 17 54 49 10 46 21 14 53 Coffee: 16 12 20 52 37 15 22 30 3 Let X ~ N(ux,o3) be the interferon gamma production for participants who drink tea and observations for the ten participants who drink tea are a random sample from X. Let Y ~ N(uy,o) be the interferon gamma production for participants who drink coffee and observations for the ten participants who drink coffee are a random sample from Y. Some R output that may help. > p1 qnorm(p1) [1] -2.326…
A researcher conducts a between-subjects study to determine whether low levels of the neurochemical serotonin leads to an increase in aggression. One sample of rats serves as a control group and receives a placebo that does not affect normal levels of serotonin. A second sample of rats receives a drug that lowers brain levels of serotonin. Using an alpha level of a = .05, the researcher then tests the animals by recording the number of aggressive responses each of the rats display. The data are as follows: a.) Step 1: State the Hypotheses Ho: H₁: Control n = 10 M = 14 SS=180.5 b.) Step 2: Determine the critical region and draw it on the distribution above: df = > *critical SM₁-M₂ Low Serotonin n = 15 M = 19 SS = 130.0 c.) Step 3: Calculate the test statistic using the provided sample data: tobs d.) Step 4: Make a decision. Circle one: Reject Null (Ho) or Fail to Reject Null (Ho) e.) State your conclusions about the research scenario in sentence form: d= f.) What is the estimated effect…
A psychologist has developed a mental alertness test. She wishes to study the effects (if any) of type of food consumed on mental alertness. Twenty-one volunteers were randomly divided into two groups. Both groups were told to eat the amount they usually eat for lunch at noon. At 2:00 P.M., all subjects were given the alertness test. Group A had a low-fat lunch with no red meat, lots of vegetables, carbohydrates, and fiber. Group B had a high-fat lunch with red meat, vegetable oils, and low fiber. The only drink for both groups was water. The test scores are shown below. Group A 75 82 96 54 78 59 67 53 97 85 66 Group B 70 80 79 60 62 71 52 69 64 88 51 74 Use a 10% level of significance to test the claim that there is no difference in mental alertness distributions based on type of lunch. (a) What is the level of significance?State the null and alternate hypotheses. Ho: Distributions are different. H1: Distributions are the same.Ho: Distributions are the same. H1:…

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