1. A psychologist is interested in studying the effects of fatigue on mental alertness. She decides to study this question using a between-subjects design. She randomly assigns individuals to two groups (Group 1 stays awake for 24 hours; Group 2 goes to sleep). After this period, each subject is tested to see how well they detect a light on a screen. The dependent variable is the subjects' number of mistakes, which reflects their mental alertness. The higher the number, the less alert they are. Here are the results from the two groups. Group 1 (Awake) Group 2 (Sleep) 5 10 mean 35 24 SS 120 270 Using an independent samplest test, answer the question of whether fatigue adversely affects mental alertness (a = 0.05). (Do this test by hand.) %3D

1. A psychologist is interested in studying the effects of fatigue on mental alertness. She decides to study this question using a between-subjects design. She randomly assigns individuals to two groups (Group 1 stays awake for 24 hours; Group 2 goes to sleep). After this period, each subject is tested to see how well they detect a light on a screen. The dependent variable is the subjects' number of mistakes, which reflects their mental alertness. The higher the number, the less alert they are. Here are the results from the two groups. Group 1 (Awake) Group 2 (Sleep) 5 10 mean 35 24 SS 120 270 Using an independent samplest test, answer the question of whether fatigue adversely affects mental alertness (a = 0.05). (Do this test by hand.) %3D

Name: 33. Independent Samples t Tests1. A psychologist is interested in stu
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Description: 33. Independent Samples t Tests1. A psychologist is interested in studying the effects of fatigue on mentalalertness. She decides to study this question using a between-subjectsdesign. She randomly assigns individuals to two groups (Group 1 staysawa

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 researcher wanted to study the tendency of people’s choices to be influenced by their environment, so she conducted an experiment. The researcher recruited 90 volunteers. She randomly assigned 30 to sit in a room with red walls, 30 to sit in a room with yellow walls, and 30 to sit in a room with orange walls. After sitting in the room for a while doing mundane activities, she offered them all a snack of strawberries, bananas, or oranges. For each individual, she recorded which room the participant was in and which snack they chose. The data are displayed in the table. The researcher would like to know if these data provide convincing evidence that the distribution of snack choice differs for the various room colors in the population of all volunteers like these. Are the conditions for inference met?
Read through this scenario and look at the data that was collected. State the null and all possible research hypotheses. Review the results below (I used SPSS) and answer the questions that follow. Scenario: A researcher wants to see if gender and / or income affects the total amount of help given to a stranger who is sitting on the side of a busy road with a sign asking for help. The independent variables are gender, income, and the interaction of gender and income. The dependent variable is total help. He wants to know if one or both factors – or the interaction of the two - affects the total amount of help offered. Because he is analyzing two independent variables (gender and income), he used a factorial ANOVA. His results show the main effect of each of the independent variables on the dependent variable (total help) and the interaction effect. The researcher is using a 95% confidence interval which means that he wants to be at least 95% sure that his independent variables…
A company wishes to evaluate the effect of package design on one of its products, a certain brand of cereal. The four package designs are to be tested in different stores throughout a large city. There are 20 stores available for the study. The amount of cereal sold is known to vary depending on the size of the stores. The 20 stores are divided into five groups of four stores each by size. The following sales figures ($1000s) were obtained after a 1-month period. Stores Design A Design B Design C Design D 1 40 33 37 38 2 45 27 32 40 3 43 31 30 41 4 44 38 40 42 5 56 45 49 42 Enter the above data into a suitable software and then conduct an analysis of variance without blocking to test whether there is evidence of a significant difference in mean sales of different package designs. Use alpha=0.01. What is the conclusion for the null hypothesis that all treatment means are equal? O Do not reject HO. There is sufficient evidence to conclude that the average sales for all stores are not…
A company wishes to evaluate the effect of package design on one of its products, a certain brand of cereal. The four package designs are to be tested in different stores throughout a large city. There are 20 stores available for the study. The amount of cereal sold is known to vary depending on the size of the stores. The 20 stores are divided into five groups of four stores each by size. The following sales figures ($1000s) were obtained after a 1-month period. Stores Design A Design B Design C Design D 1 40 33 37 38 2 45 27 32 40 3 43 31 30 41 4 44 38 40 42 5 56 45 49 42 Enter the above data into a suitable software and then conduct an analysis of variance with blocking (analyze this data as a complete block design) to test further whether there is evidence of a significant difference in mean sales of different package designs. Use alpha=0.01. What are the sums of squares for Blocks? Provide your answer to the nearest 2 decimal places.
The medical researcher is comparing two treatments for lowering cholesterol: diet and meds. The researcher wants to see if the patients who receive the recommendation to change their diet have more success lowering cholesterol compared to a prescription of meds. A random sample of some patients who received the recommendation to change their diet and others who were prescribed meds was taken. The results of how many did or did not lower their cholesterol are shown below: Data on Diet vs. Meds for Weight Loss Diet Meds Yes 424 502 No 255 320 What can be concluded at the = 0.05 level of significance? For this study, we should use Select an answer z-test for a population proportion t-test for the difference between two dependent population means t-test for a population mean z-test for the difference between two population proportions t-test for the difference between two independent population means The null and alternative hypotheses would be: Select an…
It is necessary to conduct a tukey test for musician. true false it is necessary to conduct a turkey test for song type true false It is necessary to conduct a Turkey test for the Musician X Song type interaction true false
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I am determining how effective a Drug is at reducing inflammation in individuals infected with a virus. the serum levels of antibody are measured as a measure of inflammation (less antibodies means less inflammation which decreases virus mortality) in 30 people given placebo, 30 people given 1 unit of the drug, and 30 people given 2 units of the drug. I would like to determine what levels of the drug are effective, and if there are sex-specific effects. What are the dependent and independent variables in this experiment? age _________ sex __________ antibody level _____________ treatment ___________
Suppose two variables are negatively correlated. Does the response variable increase or decrease as the explanatory variable increases?
Determine whether the study depicts an observational study or an experiment. A scientist was studying the effects of a new fertilizer on crop yield. She randomly assigned half of the plots on a farm to group one and the remaining plots to group two. On the plots in group one, the new fertilizer was used for a year. On the plots in group two, the old fertilizer was used. At the end of the year the average crop yield for the plots in group one was compared with the average crop yield for the plots in group two.
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?