If you use a 0.05 level of significance in a two tail hypothesis test, what decision will you make if z = +2.21?
Q: A researcher designs an experiment in which the single independent variable has five levels. If the…
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Q: If you use a 0.05 level of significance in a two-tail hypothesis test, what decision will you make…
A:
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Q: If you use a 0.05 level of significance in a two-tail hypothesis test, what decision will you make…
A: Solution: 4. From the given information, ZSTAT = –0.45 and the test is two-tailed.
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Q: If you use a 0.05 level of significance in a two-tail hypothesis test, what decision will you make…
A: Alpha = 0.05 Two tailed test Zstat = 1.2
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Q: A psychologist studied the effect of defendants' likeability and nervousness on willingness to…
A: The data shows the likeable or not likeable and nervous and not nervous.
If you use a 0.05 level of significance in a two tail hypothesis test, what decision will you make if z = +2.21?
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- Using the latest in medical technology, an orthopedic doctor has developed a new surgical procedure that he believes is an improvement over the standard procedure. He wants to study whether the mean recovery time of patients who have the new procedure is less than the mean recovery time of patients who have the standard procedure. The doctor studies a random sample of 11 patients who have the new procedure and a random sample of 10 patients who have the standard procedure. (These samples are chosen independently.) The doctor records each patient's recovery time (in days). These data are shown in the table. Recovery times (in days) 350, 284, 291, 393, 295, 377, 401, 371, 423, 449, 364 New procedure Standard procedure 435, 409, 419, 423, 388, 410, 412, 438, 396, 424 Send data to calculator Send data to Excel Assume that the two populations of recovery times are approximately normally distributed. Can the doctor conclude, at the 0.01 level of significance, that the population mean of the…When you get a surprisingly low price on a productdo you assume that you got a really good deal or thatyou bought a low-quality product? Research indicatesthat you are more likely to associate low price and lowquality if someone else makes the purchase rather thanyourself (Yan & Sengupta, 2011). In a similar study,n = 16 participants were asked to rate the quality oflow-priced items under two scenarios: purchased by afriend or purchased yourself. The results produced amean difference of MD = 2.6 and SS = 135, with selfpurchases rated higher.a. Is the judged quality of objects significantly different for self-purchases than for purchases made byothers? Use a two-tailed test with a = .05.b. Compute Cohen’s d to measure the size of thetreatment effect.A group of statisticians decides they will answer the question: Has the wolf reintroduction to Yellowstone been detrimental to elk herds in the park? They decide that each of the four data scientists will take a quadrant of the park to collect a sample from as randomly as possible. They decide they will collect the sample during the winter, the time the elk herds are most stressed. They agree to trust each others professional judgement when it comes to the health of the individual elk in the herd. They will give each elk a grade out of 3pts: 1 pt for sick, 2pts for fair, and 3pts for healthy. They then share their data and compare to create a final report on the overall health of the elk in the park. In this scenario, what is the same for all samples (the control)?
- A researcher predicted that students will learn better if they attribute their performance to effort rather than natural ability. In one condition, a randomly selected group of sixth graders wrote an essay about a time when they worked hard to reach a goal. In a second condition, a different randomly selected group of sixth graders wrote about a skill they thought they were naturally good at. Afterwards, the students began a nine-week social studies unit that concluded with an achievement test. Use the data below to conduct an 1. appropriate statistical test (higher scores indicate higher achievement). Follow the 7 hypothesis testing steps you have been taught. Some of the steps have already been done for you. Wrote about Wrote about effort natural ability 81.89 M 84.77 40 55 60 60 1. Ho: There is no difference in the achievement scores of the students who wrote about effort and those who wrote about natural ability Mefort = Hability Ha: There is a difference in the achievement scores…A group of statisticians decides they will answer the question: Has the wolf reintroduction to Yellowstone been detrimental to elk herds in the park? They decide that each of the four data scientists will take a quadrant of the park to collect a sample from as randomly as possible. They decide they will collect the sample during the winter, the time the elk herds are most stressed. They agree to trust each others professional judgement when it comes to the health of the individual elk in the herd. They will give each elk a grade out of 3pts: 1 pt for sick, 2pts for fair, and 3pts for healthy. They then share their data and compare to create a final report on the overall health of the elk in the park. In this scenario, what is one of the factors that could negatively effect sample collection?Q2 A study was conducted to test the effect of melatonin on female dementia patients. A random sample of 10 patients was given a dose of 2.5 mg of melatonin daily, while a control group of 10 patients was given a placebo. The data below are the subjective well-being scores for each of the patients after two months on the assigned treatment. Higher scores indicate greater well-being. Is there a difference in mean well-being score between the two treatments? Assume Equal Variances. Run the test at a 5% level of significance. 1 ) the appropriate null and alternative hypotheses ( 2) the appropriate test ); 3) the decision rule ; 4) the calculation of the test statistic, 5) your conclusion including a comparison to alpha or the critical value, What do the results mean?
- According to the most recent General Social Survey, 70% of adults watch TV nightly. A researcher believes that the proportion of college students who watch TV nightly is less than this. To test this claim the research samples 400 college students and finds that 276 watch TV nightly. At the 0.05 level of significance does this data provide evidence to suggest that the proportion of college students who watch TV nightly is less than 70%? Select the correct hypothesis test for this problem:A team of researchers would like to determine whether the number of households that use the internet for more than an hour a day is greater in large cities or small towns. To do so, the researchers take two random samples. The first sample consists of randomly selected people who live in cities with more than 500,000 people around the country. The second sample consists of randomly selected people who live in towns with fewer than 20,000 people. Are these samples dependent or independent? Select the correct answer below: O These samples are independent. O These samples are dependent. Not enough information is provided to determine independence.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?
- In a survey of working parents (both parents working), one of the questions asked was "Have you refused a job, promotion, or transfer because it would mean less time with your family?" 410410 men and 410410 women were asked this question. 26%26% of the men and 19%19% of the women responded "Yes". Based on this survey, can it be concluded that there is a difference in the proportion of men ( p1p1 ) and women ( p2p2 ) responding "Yes"? Use a significance level of α=0.05α=0.05 for the test. Step 3 of 5 : Compute the value of the test statistic. Round your answer to two decimal places.Classify the hypothesis test as two-tailed, left-tailed, or right-tailed. At one school, the average amount of time that tenth-graders spend watching television each week is 20.1 hours. The principal introduces a campaign to encourage the students to watch less television. One year later, the principal wants to perform a hypothesis test to determine whether the average amount of time spent watching television per week has decreased from the previous mean of 20.1 hours.Using the latest in medical technology, an orthopedic doctor has developed a new surgical procedure that he believes is an improvement over the standard procedure. He wants to study whether the mean recovery time of patients who have the new procedure is less than the mean recovery time of patients who have the standard procedure. The doctor studies a random sample of 11 patients who have the new procedure and a random sample of 9 patients who have the standard procedure. (These samples are chosen independently.) The doctor records each patient's recovery time (in days). The patients who had the new procedure have a sample mean recovery time of 367.3 with a sample variance of 2851.8. The patients who had the standard procedure have a sample mean recovery time of 420.9 with a sample variance of 98.1. Assume that the two populations of recovery times are approximately normally distributed. Can the doctor conclude, at the 0.01 level of significance, that the population mean of the…