A research team collected data on the time college students spent on an ordinary homework assignments

A recent study of 1000 high school juniors and seniors asked whether or not they felt smartphones are a valuable learning tool. Additional data were gathered on their smartphone plan (unlimited data, additional texting, or standard voice plan) and which class they were in (junior vs. senior). Which of the following is a correct pair of hypotheses the researchers could test? (A) Ho: The proportion of juniors and seniors who feel smartphones are a valuable learning tool is the same for students that have each type of plan. Ha: The proportion of juniors and seniors who feel smartphones are a valuable learning tool is not the same for students that have each type of plan (B) Ho: The proportion of students who feel smartphones are a valuable learning tool is the same for students that have each type of plan. Ha: The proportion of students who feel smartphones are a valuable learning tool is not the same for students that have each type of plan. (C) Ho: There is an association between class…

In​ soccer, serious fouls result in a penalty kick with one kicker and one defending goalkeeper. The accompanying table summarizes results from 295 kicks during games among top teams. In the​ table, jump direction indicates which way the goalkeeper​ jumped, where the kick direction is from the perspective of the goalkeeper. Use a 0.05 significance level to test the claim that the direction of the kick is independent of the direction of the goalkeeper jump. Do the results support the theory that because the kicks are so​ fast, goalkeepers have no time to​ react, so the directions of their jumps are independent of the directions of the​ kicks?   Goalkeeper Jump     Left Center Right   Kick to Left 59 3 37   Kick to Center 42 8 31   Kick to Right 47 5 63

A small pilot study is run to compare a new drug for chronic pain to one that is currently available. Participants are randomly assigned to receive either the new drug or the currently available drug and to report improvement in pain on a 5-point ordinal scare: 1= pain is much worse,2=pain is slightly worse,3=no change,4=pain improved slightly,5= pain much improved.Is there a significance difference in self reported improvement in pain? Use the Mann-Whitney U test with a 5% level of significance.       New Drug: 4 5 3 3 4 2       Standard Drug: 2 3 4 1 2 3

According to a book published in 2011, 45% of the undergraduate students in the United States show almost no gain in learning in their first two years of college (Richard Arum et al., Academically Adrift, University of Chicago Press, Chicago, 2011). A recent sample of 1540 undergraduate students showed that this percentage is 37%. Can you reject the null hypothesis at a 2.5% significance level in favor of the alternative that the percentage of undergraduate students in the United States who show almost no gain in learning in their first two years of college is currently lower than 45%. Use both the p-value and the critical-value approaches. Round your answers for the observed value of z and the critical value of z to two decimal places, and the p-value to four decimal places. Zobserved = p-value = Critical value = i Hence we can conclude that the percentage of undergraduate students in the U.S. who show almost no gain in learning in their fırst two years of college is currently 45%.

In reading the results of a multiple regression analysis that contained 4 predictor variables, the researcher noticed a column labeled Beta. Two of the Beta’s were positive and two were negative. He concluded that a.) Beta’s that were positive were statistically significant b.) Beta’s that were positive had more of an effect c.) Beta’s that were positive were associated with increases in the criterion variable d.) Beta’s that were positive did not affect the criterion because they were “controlled for…”

Researchers studying the link between prenatal vitamin use and autism surveyed the mothers of a random sample of children aged 24 - 60 months with autism and surveyed another separate random sample for children with typical development. Table summarizing the number of mothers in each group who did and did not use prenatal vitamins during the three months before pregnancy (data from Schmidt, 2011) Autism Typical Development Total No vitamin 111 70 181 Vitamin 143 159 302 Total 254 229 483 Complete the hypothesis test for independence between the two variables, use of prenatal vitamins during the three months before pregnancy and autism in Rguroo. What is the value of the test statistic for this test? (Use the Large Sample Z method and please round to two decimal places)

Indicate whether CPAs in states that have flat state income tax rates work fewer hours per week during tax season compared to the US average. You will want to formally set up H0 and Ha, report either the test statistic (z-value) or p-value, and explain why you either reject or fail to reject your null hypothesis.

Do less agreeable Facebook users tend to spend more time on Facebook? A study (Ivcevic and Ambady, 2013) aimed to investigate various facets of use of the social networking website Facebook. Previous research suggested that individuals with poorer face-to-face social skills may find internet-based social platforms less daunting, so as part of the study Ivcevic and Ambady investigated whether an individual's volume of Facebook use was associated with levels of "agreeableness". The subjects were 99 university students who all had a Facebook page. The subjects agreed to allowing the content of their Facebook pages to be downloaded on six separate occasions over a three-week period. As part of the data gathered on each subject, each of the 99 were individually rated by a selected friend on an "agreeableness" scale (based on average ratings on a questionnaire where all responses were on a Likert scale), with 1 being "low" and 5 "high". We consider here the relationship between "friend…

4. In the past, the mean running time for a certain type of cell phone battery has been 19.2 hours. The manufacturer has introduced a change in the production method and wants to perform a hypothesis test to determine whether the mean running time has increased as a result. The hypotheses are: Họ: u=19.2 hours H1: µ>19.2 hours Explain the meaning of a Type I error. A) Concluding that u> 19.2 hours when in fact u = 19.2 hours B) Concluding that u 19.2 hours C) Concluding that u = D) Concluding that u> 19.2 hours when in fact u> 19.2 hours 19.2 hours when in fact u > 19.2 hours