What are the equations for a two-tailed hypothesis test?

Exercise 2: The school board of Two Guns, Texas is deeply concerned that their public school teachers are quitting their jobs and accepting teaching positions in other parts of the state. Some members of the school board think that the reason why teachers are quitting is because their weekly salaries are lower than those offered by other school boards in the state. The school board hires you to conduct a significance test. The research question: Do teachers in other parts of Texas earn higher average weekly salaries than those working in the Two Guns school district? There is no estimate of the population standard deviations. The significance level will be set at 5%. Step 1: Test Set-up Question 1: How large a sample is needed to achieve 80% statistical power? Based on past research Cohen's d effect size is estimated at 0.40, which is a small effect. See the table below: Cohen's d ES Thresholds Small 0.2 Medium 0.5 Large 0.8 Here are the results of an a priori power analysis run using…

Hypothesize signs, define your null and alternative hypothesis. Do the estimated coefficients have their expected signs? Explain..

Herbal cancer A report in the New England Journal of Medicine notes growing evidence that the herb Aris-tolochia fangchi can cause urinary tract cancer in those who take it. Suppose you are asked to design an experi-ment to study this claim. Imagine that you have data on urinary tract cancers in subjects who have used thisherb and similar subjects who have not used it and thatyou can measure incidences of cancer and precancerouslesions in these subjects. State the null and alternativehypotheses you would use in your study.

Sh/question/an-airline-offers-discounted-advance/ ADER SUBJECTS v Upper level math > Statistics question & answer logicfail2 Asked 2 yrs ago. An airline offers discounted "advance purchase " fares to customers who buy tickets more than 30 days before travel and charges "regular" fares for tickets purchased during those last 30 days. The company has noticed that 60% of its customers take advantage of the advance-purchase fares. The "no-show" rate among people who paid regular fares is 30%, but only 5% of customers with advance-purchase tickets are no-shows. a) What percent of all ticket holders are no-shows? b) What 's the probability that a customer who didn't show had an advance -purchase ticket? c) Is being a no-show independent of the type of ticket a passenger holds? Explain. 5.0 * 09 Sarah Schrijvers a) The percent of no-shows is the percent of no-shows of advance-purchase tickets increased by the percent of no-shows of advance purchase tickets: P(no-show) = 0.6 × 0.05+0.4 × 0.3…

Solve the last question please

using Excel

Up-County Associates is hired to estimate the proportion of county households that own three or more automobiles. They conducted their survey using a simple random sample of 250 randomly selected households and found that 23% of those households owned three or more automobiles.    (a)    Is the proportion, 23%, a parameter or a statistic? Explain.       (b)    If Up-County Associates were to continually choose simple random samples of 250 randomly selected households, each time recording the proportion of households in the sample owning three or more automobiles, what would be the “shape” of the resulting distribution of all these sample proportions?  Explain.             (c)    Suppose now that survey company Lower-County Polling also conducted a survey to determine the proportion of county households that own three or more automobiles, but they surveyed only 100 randomly selected households. If Lower-County Polling were also to sample over and over again (using simple random samples…

Review of Independent t-test Base your answers on the following problem and data. A student researcher wants to test the hypothesis that students who are made to feel anxious by a critical teacher cannot learn math concepts as well as students who are assigned to a supportive teacher. For the student's 301 project, the student recruits 14 participants and randomly assigns the participants to learn new math concepts from either a critical (n=7) or supportive teacher (n=7). All other variables are kept the same; in fact, a single person performs the roles of both the supportive and critical teacher, but just modifies her behavior accordingly. Each group of participants then takes a test after the math lesson and their scores on the test are measured. Here is the resulting data: Critical Teacher 27 25 19 10 16 22 14 Supportive Teacher 25 29 18 23 20 15 19

USE THE 8-STEP HYPOTHESIS TESTING Refer to the study by Carter et al. [A-9], who investigated the effect of age at onset of bipolar disorder on the course of the illness. One of the variables studied was subjects' family history. Table 3.4.1 shows the frequency of a family history of mood disorders in the two groups of interest: early age at onset (18 years or younger) and later age at onset (later than 18 years). Family History of Mood Disorders Early ≤ 18(E) 28 19 41 53 Later > 18 (L) 35 38 44 60 141 Total 63 57 85 113 Negative (A) Bipolar disorder (B) Unipolar (C) Unipolar and bipolar (D) Total 177 318 Source: Tasha D. Carter, Emanuela Mundo, Sagar V. Parkh, and James L. Kennedy, "Early Age at Onset as a Risk Factor for Poor Outcome of Bipolar Disorder," Journal of Psychiatric Research, 37 (2003), 297-303. Can we conclude on the basis of these data that subjects 18 or younger differ from subjects older than 18 with respect to family histories of mood disorders? Let a = .05.