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    Hypothesis Testing

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    T-Statistics Independent Samples

    Numeric results for several independent-samples t tests are presented here. Decide whether each test is statistically significant, and report each result in the standard APA format. a. A total of 73 people were studied, 40 in one group and 33 in the other group. The test statistic was calculated as 2.126 for a two-tailed test

    Comparing Outcomes of Two Datasets

    1.7 0.7 -0.1 -0.7 -3.5 14.9 3.5 17.1 -7.6 1.6 11.7 6.1 1.1 -4.0 20.9 -9.1 2.1 -1.4 1.4 -0.3 -3.7 -0.8 2.4 12.6 1.9 3.9 0.1 15.4 -0.7 0 You obtain the data shown below for 30 girls with anorexia who were treated with psychodynamic

    Population Mean Waiting Time

    a) You are the manager of a fast food restaurant. You want to determine whether the population mean waiting time to place an order has changed in the past month from its previous population mean value of 4.5 minutes. From past experience, you can assume that the population is normally distributed with a population standard dev

    Direction of a Test

    10 Test the claim below about the mean of the difference of two populations. Use a t-test for dependant, random samples at the given level of significance with the given statistics. Is the test right-tailed, left-tailed, or two-trailed? Assume the populations are normally distributed. Is the test right-tailed, left-taile

    Uniform distribution of bicycle accidents

    A bicycle safety organization claims that fatal bicycle accidents are uniformly distributed throughout the week. The table below shows the day of the week for which 778 randomly selected fatal bicycle accidents occurred. At ? = 0.10, can you reject the claim that the distribution is uniform? Complete parts (a) through (d) bel

    Random Sampling Distribution Test

    An automobile manufacturer advertises that the mean petrol consumption of its new hybrid car does not exceed 4.6 litres per 100 km. An independent company decides to test the manufacturer's claim by selecting a random sample of 16 vehicles and measuring the consumption of each. They have found that the petrol consumptions in lit

    Errors and Their Implications

    It has been said that from the point of view of the general population, Type I errors are particularly undesirable. This has been used as a justification for setting alpha at such low levels as .05 and .01. Does this make sense? Explain your response. What are the implications of making a Type I error, as compared to those o

    Testing Assumptions.

    For its validity, all hypothesis testing depends heavily on the assumption that the sample that is used was drawn using probability sampling techniques. Why is this important? What can you do if you just cannot use a probability sampling technique? (For example, suppose there is no good sampling frame available for the popul

    One-tailed and Two-tailed Tests

    You are doing a study examining the effects of studying method on academic achievement. All the students in your study take a course on genetics that lasts for 10 days. One group of students studies 20 minutes a day for 10 days. The second group studies once at the end of the course but for 200 minutes. What is a one-tailed t

    Hypothesis - Tests and Errors

    With each hypothesis, indicate whether the appropriate analysis would be a one-tailed test or a two-tailed test and indicate a type I and type II error, given the context of the hypothesis. Hypothesis: 1. The three treatments tested differ in how well they work. 2. Children receiving supportive therapy will get worse ov

    Hypothesis Testing: One Sample Inference

    Diabetes Plasma-Glucose levels are used to determine the presence of diabetes. Suppose the mean in (plasma-glucose) concentration (mg/dL) in 35 to 44-year-olds is 4.86 with standard deviation = 0.54. A study of 100 sedentary people in this group is planned to test whether they have a higher or lower level of plasma glucose t

    Statistics - Critical Values

    Write the claim mathematically and identify Hₒ and Hₐ. (b) Find the critical value(s) and identify the rejection region(s). (c) Find the standardized test statistic. (d) decide whether to reject or fail to reject the null hypothesis. A medical researcher says that at least 24% of adults are smokers. In a random sample o

    Case 3: Grocery4You.com

    e-grocers are companies that sells groceries over the internet. Customers open an online account, enter their orders, pay by credit card or debit card, and receive deliveries by truck. Several businesses think that it is means of convenience for busy customers who have no or very little time to go to a grocery store, buy groce

    Hypothesis Testing Exercise

    M&Ms® Project Part 5 Test the hypothesis (α = 0.05) that the population proportions of red and brown are equal (pred = pbrown). You are testing if their proportions are equal to one another, NOT if they are equal to one another AND equal to 13%. NOTE: These are NOT independent samples, but we will use this approach any

    Concepts and properties of the hypothesis testing.

    1. a) What is a hypothesis? Specifically, is it a statement about the population or the sample? b) What is the purpose of hypothesis testing? c) How is the role of the null hypothesis different from that of the research (alternative) hypothesis? d) Provide an example of a hypothesis test you could conduct at work

    Self-Reported & Measured Male Heights

    As part of the National Health and Nutrition Examination Survey, the Department of Health and Human Services obtained self-reported heights and measured heights for males aged 12-16. All measurement is in inches. Listed below are sample results. a. Is there sufficient evidence to support the claim that there is a difference b

    Sample proportion question

    When an election for political office takes place, the television networks cancel regular programming and instead provide election coverage. When the ballots are counted, the results are reported. However, for important offices such as president or senator in large states, the networks actively compete to see which will be the f

    Comparing p value method, hypothesis test and confidence interval.

    A student of the author surveyed her friends and found that among 20 males, 4 smoke and among 30 female friends, 6 smoke. Give two reasons why these results should not be used for a hypothesis test of the claim that the proportions of male smokers and female smokers are equal. Given a simple random sample of men and a simple ra

    Statistics Enriching and Representing the Results of a Study

    Based on what we know about statistics and using a real example, how do you believe statistics can enrich and represent the results of a study? How can statistics be used to misrepresent the results of a study? With these thoughts in mind: Write an example, a description of how you believe statistics can enrich and repres

    Average grade for all people who take a class is 83

    Suppose that the average grade for all people who take a class is 83 with a standard deviation of 3.5. If your particular class has an average of 89, can you conclude that your class is better than average at the 90 percent confidence level? Label and describeeach step of the hypothesis testing procedure, and be sure to specify

    Correlation questions

    1. For the following scores, X Y 3 6 6 1 3 4 3 3 5 1 a) Find the regression equation for predicting Y from X b) Calculate the predicted Y value for each X 2. For the following scores X Y 1 6 4 1 1 4 1 3 3

    How Correlation is Often Miscast as Causation

    Think about how correlation is often miscast as causation. That is, cause is attributed to a variable when in fact, there is no causal relationship but only a correlation between the two variables. Consider that of massive gun violence and being raised in a broken family when looking at correlations to use and explain as a

    Applied Statistics in Nursing Question

    Researchers routinely choose an ?-level of 0.05 for testing their hypotheses. What are some experiments for which you might want a lower ? -level (e.g. 0.01)? What are some situations in which you might accept a higher level (e.g. 0.1)?

    Is Correlational study a good choice?

    I have to develop a research design for a pretend study. It will be quantitative to study the effects of linguistic modification on nursing exams for one year. The original exam and the modified exam will be randomly assigned to students (native English speakers and English as a second language students). There would be scores f

    Wilcoxon Rank Sum Test: Primary Care

    Use the Wilcoxon rank rum test. Assume that the samples are independent. Also perform each of these steps. state the hypothesis and identify the claim find the critical value compute the test value make the decision summarize the results. Samples of enrollments from medical schools that specialize in research and in pr

    Hypothesis Testing & Confidence Interval: M&M Candies

    Construct a 95% confidence interval for the proportion of red candies. Using your same data determine if the proportion of green candies in a package of M&Ms is different than what is claimed by the company. List null and alternative hypothesis, the test-statistic and the p-value. If you wanted to estimate the proportion of

    Emotional Responses to Classical Music

    Steven collected data from 20 college students on their emotional responses to classical music. Students listened to two 30-second segments from "The Collection from the Best of Classical Music." After listening to a segment, the students rated it on a scale from 1 to 10, with 1 indicating that it "made them very sad" to 10 in