6.A researcher hypothesizes that people who are allowed to sleep for only four hours willscore significantly lower than people who are allowed to sleep for eight hours on acognitive skills test. He brings sixteen participants into his sleep lab and randomly assignsthem to one of two groups. In one group he has participants sleep for eight hours and inthe other group he has them sleep for four. The next morning he administers the CAT( Cognitive Ability Test) to all participants. (Scores on the CAT range from 1-9 with high scores representing better performance). Use t-test with a = .05, 2-tailed, to prove theresearcher's hypothesis.CAT scores8 hours sleep5 75 3 5 3 3 9group (X)4 hours sleep8 1 4 6 6 4 1 2group (Y)

In the given case the researcher is hypothesizing that less-sleep group (group X) score will not be…

Answered: 6. A researcher hypothesizes that…

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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3. Bayesian Inference A cab was involved at night in a hit and run accident. In this town there are only two cab companies, the Blue with 80% of the cabs and the Green company with the remaining 20%. As it happened there was a witness to the accident who identified the hit and run cab as Blue. The case came to trial. An important part of the testimony was a test of the reliability of the eyewitness to identify a cab as being either Blue or Green under the same circumstances as those that existed the night of the accident. The result of these tests was that the witness correctly identified a blue cab as blue 70% of the time and a green cab as green 80% of the time. On the basis of the claim of the eyewitness and the test conducted by the court, what is the probability that the cab involved in the accident was in fact Blue as the witness had claimed?
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 67 93 82 69 76 47 43 58 92 63 52 Group B 70 57 75 59 66 49 55 46 45 91 89 72 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? (b) Compute the sample test statistic. (Use 2 decimal places.) (c) Find the P-value of the sample test statistic. (Use 4 decimal places.)
A teacher believes that students who study more than four hours for her tests will do better than students who do not study for her tests. To test this belief, the teacher recruited 16 students and randomly assigned them to two groups: G1: a group of n1=8 students that studied more than four hours for her test, and G2: a group of n2=8 students that did not study for her test. The following are the data from G1, who studied more than four hours for the test: n1=8 M1=85 s1=5 (this is the standard deviation of the sample, dividing the sum of squares by n1) The following are the data from G2, who did not study for the test: n2=8 M2=75 s2=4 (this is the standard deviation of the sample, dividing the sum of squares by n2) Perform a t-test by answering the questions below. Use an alpha-level of α=.05. 0. Using formulas from Section 4, compute the estimates of the population variances, est. σ12 and est. σ22 (from s1 and s2 above). 1. What is the research…
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A psychologist wants to know whether viewing more violent TV shows affects aggressive behavior. 12 children were chosen at random for an experiment and randomly allocated to one of two conditions. In condition 1, six kids were given an aggressive behavior test. The more aggressive the conduct, the higher the score. In condition 2, six children were given the identical test after watching two hours of tv shows. The following results were obtained. Condition 1 5 14 6 8 7 6 Condition 2 12 14 14 8 15 9 Assume the obtained value of the appropriate statistic is t obt = -2.431, using α = 0.05, 2 tail, and t crit = +2.228 and -2.228, what do you conclude? a. retain null hypothesis, suggesting that violent TV show does not affect aggression. b. reject null hypothesis, suggesting that violent TV show affects aggression.
Example 4.7 Out of 1800 candidates appeared for a competitive examination 625 were successful; 300 had attended a coaching class and of these 180 came out successful. Test for the association of attributes attending the coaching class and success in the examination.
To investigate whether it helps to have a "white-sounding" first name when looking for a job, the researchers sent 5,000 resumes in response to ads that appeared in magazines. The resumes were identical except that 2,500 of them had "white-sounding" first names, such as Brett and Emily, whereas the other 2,500 had "black-sounding" names such as Tamika and Rasheed. Resumes of the first type elicited 251 responses and resumes of the second type only 169 responses. A button hyperlink to the SALT program that reads: Use SALT. Do these data support the theory that the proportion receiving responses is greater for those resumes with "white-sounding first" names? (Use ? = 0.05. Use pwhite-sounding − pblack-sounding.) Find the test statistic. (Round your answer to two decimal places.) z = Find the P-value. (Round your answer to four decimal places.) P-value = State your conclusion. Reject H0. We have convincing evidence that the proportion eliciting responses is higher for…
An anger-management course claims that, after completing its seminar, participants will lose their tempers less often. Always a skeptic, you decide to test this claim. A random sample of 12 seminar participants is chosen, and these participants are asked to record the number of times that they lost their tempers in the two weeks prior to the course. After the course is over, the same participants are asked to record the number of times that they lost their tempers in the next two weeks. The following table lists the results of the survey. Using these data, test the claim at the 0.01 level of significance assuming that the population distribution of the paired differences is approximately normal. Let participants before completing the anger-management course be Population 1 and let participants after completing the anger-management course be Population 2. Number of Times Temper Was Lost during a Two-Week Period Before 10 6 8 10 6 3 10 3 8 After 6 7 4 4 8 6 4 9 3 7 Copy Data Step 2 of 3:…
24) Some research has shown that swearing can help reduce ratings of pain (Stephens, Atkins, & Kingston, 2009). In one such study, each participant was asked to plunge a hand into icy water and keep it there as long as the pain would allow. In one condition, the participants repeated their favorite curse words while their hands were in the water. In the other condition, the participants repeated a neutral word. In addition to lowering the participants’ perception of pain, swearing also increased the amount of time they were able to tolerate the pain. Data similar to the results obtained in their study are shown in the following table. Amount of Time (in Seconds) Participant Swear Words Neutral Words 1 94 59 2 70 61 3 52 47 4 83 60 5 46 35 6 117 92 7 69 53 8 39 30 9 51 56 10 73 61 Do these data indicate a significant difference in pain tolerance between the two conditions?…
A social psychologist wants to investigate whether stereotypes can be used to achieve positive outcomes. To explore this, the researcher randomly assigns 9 females to one condition in which participants were primed with a positive stereotype where they were asked to read a paragraph reminding them that Asians are stereotypically believed to be good at mathematics. Another 9 participants were primed with a neutral paragraph stating that many individuals find mathematics difficult and that many overcome this difficulty by focusing on the task at hand. After reading their assigned paragraph, both groups then completed a series of timed mathematical tasks. Adopting a significance or alpha-level of 5% (i.e., .05 probability), what is the two-tailed critical t value cut-off for this study? ±2.120 ±2.307 ±2.263 ±2.110
Suppose a researcher is interested in examining the relationship between a person's gender and whether he or she likes the taste of Vegemite (a dark- brown food paste, made from yeast, that is popular in Australia). She collects a sample of n = 10 people and asks them whether they like the taste of Vegemite. The following table summarizes the results. Male Female Does Not Like the Taste of Vegemite 4 1 Likes the Taste of Vegemite 2 3 The researcher wants to calculate the correlation between a person's gender and whether he or she likes the taste of Vegemite. To do so, the researcher first creates a table of the data by converting each variable to a numerical value. She assigns 0 to "male" and 1 to "female." She then assigns 0 to "does not like the taste of Vegemite" and 1 to "likes the taste of Vegemite."
A high school track coach wanted to test whether giving the students an energy drink could affect performance during the 100 meter race. The coach split the 26 boys into two equal sized groups, where Group 1 was given the energy drink and Group 2 was not. The 100 meter race times were recorded during practice and shown in the table below. What inference can be made about the results? Group 1 Group 2 12.2 13 12.5 12.3 13.3 12.8 12.9 13 13 13.8 12.1 13 13 13 13 13 12.1 13 13 13 12.1 13 12.8 13 13 12.6 Mean: 12.7 Mean: 13 Since the simulation shows ( many cases or free cases )? where a mean difference of ( solve for this answer ) or less occurred when the groups were re-randomized, it can be inferred that the mean difference observed in the study was ( very possibly or very unlikely ) ?due to the random assignment of participants into groups, so the results of the study are (…

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