What is the power of a study using a correlation, with a one-tailed test at the .05 significance level, in which the researchers predict a large effect size and there are 50 participants? How many participants do you need for 80% power in a planned study in which you predict a small effect size and will be using a correlation, one-tailed, at the .05 significance level?

A sociologist claims that the students’ college GPA’s in unrelated to their families’ incomes. For a random sample of 20 students the coefficient of correlation was computed as 0.40. Using the 0.01 significance level, do the formal hypothesis test.Remember to show your steps (including all relevant information) show the steps on how to solve it

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?

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In a fishing lodge brochure, the lodge advertises that 75% of its guests catch northern pike over 20 pounds. Suppose that last summer 71 out of a random sample of 86 guests did, in fact, catch northern pike weighing over 20 pounds. Does this indicate that the population proportion of guests who catch pike over 20 pounds is different from 75% (either higher or lower)? Use ? = 0.05.   (a) What is the level of significance?   State the null and alternate hypotheses. H0: p = 0.75; H1: p > 0.75H0: p ≠ 0.75; H1: p = 0.75    H0: p < 0.75; H1: p = 0.75H0: p = 0.75; H1: p ≠ 0.75H0: p = 0.75; H1: p < 0.75 (b) What sampling distribution will you use? The Student's t, since np > 5 and nq > 5.The standard normal, since np > 5 and nq > 5.    The Student's t, since np < 5 and nq < 5.The standard normal, since np < 5 and nq < 5. What is the value of the sample test statistic? (Round your answer to two decimal places.)   (c) Find the P-value of the test…

When you get a surprisingly low price on a product do you assume that you got a really good deal or that you bought a low-quality product?  Research indicates that you are more likely to associate low price and low quality if someone else makes the purchase rather than yourself.  In a similar study, 16 participants were asked to rate the quality of low-priced items under two scenarios:  purchased by a friend or purchased yourself.  The results produced a mean difference of 2.6 and a SS = 135, with self-purchases rated higher.  Is there evidence that the judged quality of objects significantly increase for self-purchases than for purchases made by others?  Please use a one-tailed test with level of significance of 5%.

You are conducting a study to see if the proportion of voters who prefer the Democratic candidate is significantly larger than 50% at a level of significance of a = 0.10. According to your sample, 49 out of 92 potential voters prefer the Democratic candidate.

Would you favor spending more federal tax money on the arts? Of a random sample of n1 = 204 women, r1 = 70 responded yes. Another random sample of n2 = 178 men showed that r2 = 48 responded yes. Does this information indicate a difference (either way) between the population proportion of women and the population proportion of men who favor spending more federal tax dollars on the arts? Use ? = 0.05.   (a) What is the level of significance?State the null and alternate hypotheses. H0: p1 = p2; H1: p1 > p2H0: p1 = p2; H1: p1 < p2    H0: p1 = p2; H1: p1 ≠ p2H0: p1 < p2; H1: p1 = p2 (b) What sampling distribution will you use? What assumptions are you making? The standard normal. We assume the population distributions are approximately normal.The Student's t. The number of trials is sufficiently large.    The standard normal. The number of trials is sufficiently large.The Student's t. We assume the population distributions are approximately normal. What is the value of the sample…

Acne is a common skin disease that affects most adolescents and can continue into adulthood. A study compared the effectiveness of three acne treatments and a placebo, all in gel form, applied twice daily for 12 weeks. The study's 517 teenage volunteers were randomly assigned to one of the four treatments. Success was assessed as clear or almost clear skin at the end of the 12 week period. The results of the study can be seen in the table below. Using the appropriate statistical test, determine if there is significant evidence that the four treatments perform differently. If so, how do they compare.

Management of a theater in a large city wants to know whether its popularity increased after it ran a popular musical. According to a previous study, 25% of city residents said they had been to the theater in the past year. A more recent study, conducted after the musical had run for a year, found that 156 of 536 residents sampled said they had been to the theater in the past year.  Is there evidence at the ? = 0.05 level that the number of residents who have been to the theater has increased in the last year?