State the null hypothesis for: An experiment testing whether echinacea decreases the length of colds. A correlational study on the relationship between brain size and intelligence. An investigation of whether a self-proclaimed psychic can predict the outcome of a coin flip. A study comparing a drug with a placebo on the amount of pain relief. (A one-tailed test was used.)

I need the answer to this question, please? An article included a summary of findings regarding the use of SAT I scores, SAT II scores, and high school grade point average (GPA) to predict first-year college GPA. The article states that "among these, SAT II scores are the best predictor, explaining 17 percent of the variance in first-year college grades. GPA was second at 15.5 percent, and SAT I was last at 13.5 percent." If the data from this study were used to fit a least squares line with y = first-year college GPA and x = high school GPA, what would the value of r2 have been? r2 =

A high school conducts a dependent sample experiment to test if there is a difference between the number of times students are absent in the fall and winter months. You have data for the following 5 students: STUDENT FALL WINTER 1 2 3 4 5 2 0 1 2 O What do you conclude about this school's absences? (Assume standard a = 0.05) 2 1 2 4 T O There is no difference between the Fall and Winter months. O There is a statistically significant difference between the Fall and Winter months. There is a difference but it is only somewhat statistically significant. There is not enough data to determine if there is a difference in absences.

You recently completed an experiment concerning the effects of carbs on happiness. One group of 11 people are assigned a high carb diet, another group of 11 people are assigned a moderate-high carb diet, another group of 11 people are assigned a moderate-low carb diet, and a final group of 11 people are assigned a low carb diet. If I find that I fail to reject the null hypothesis, what might my next step be? Group of answer choices Change my analysis and alpha to make the finding significant and then run post-hoc tests. 1. Run multiple dependent measures t-tests to see if there are any significant differences between particular groups 2. Run multiple independent samples t-tests to see if there are any significant differences between particular groups 3. Change my hypothesis to see if I can find something significant with a different hypothesis for this study 4. Run home and binge-watch Bridgerton because there is nothing else that should be done statistically

What are the independent and dependent variables for the following examples? What statistical test would you use for each of the following scenarios? What would you set your alpha-level at? Sally wants to examine whether there is a difference in muscular strength between participants who engaged in an 8-week resistance training program and participants who engaged in an 8-week endurance training program. The participants only took part in one of the 8-week programs, not both. What test would she use to determine whether the differences in muscular strength are significant? Why?

College students and STDs: A recent report estimated that 25% of all college students in the United States have a sexually transmitted disease (STD). Due to the demographics of the community, the director of the campus health center believes that the proportion of students who have a STD is higher at his college. He tests H0: p = 0.25 versus Ha: p > 0.25. The campus health center staff select a random sample of 150 students and determine that 43 have been diagnosed with a STD. Conduct a hypothesis test to address the director’s hypothesis. Use a 5% significance level to make your decision. Use the applet to determine the P‑value. Click here to open the applet. Which of the following is an appropriate conclusion based on the results?  The data provides strong evidence that the proportion of students at his college who have a STD is more than 25%.  The data suggests that the proportion of students at his college who have a STD is 29%.  Of the students surveyed at his college, 29%…

Effect size is the amount of statistical importance a particular finding has in psychological practice. the power of a study divided by the sample size. the sample size multiplied by 1 – beta.  the degree to which an experimental manipulation separates two populations.

Impact of College Roommates on Grades In this exercise, we investigate answers to the questions: How much of an effect does your roommate have on your grades? In particular, does it matter whether your roommate brings a videogame to college? A study was conducted involving n = 210 first-year students who were randomly assigned a roommate. Table 1 gives summary statistics on grade point average (GPA) for the first semester depending on whether the student and/or the roommate brought a videogame to campus. Student brought videogame No Yes No Yes Roommate brought videogame No No Yes Yes Sample size 88 44 38 40 Mean GPA 3.128 3.039 2.932 2.754 Table 1 Videogames and GPA St. Dev. 0.590 0.689 0.699 0.639 Considering only students whose roommate does not bring a videogame to campus, find a 99% confidence interval for the difference in mean GPA between students who bring a videogame and those who do not bring a videogame μN - My, where μ represents the mean GPA for students who do not bring a…

Which of the following is not a sample property of OLS?   a. Sample covariance of  each included variable and the residuals is zero   b. the sum of all residuals is zero   c. the average of all residuals is zero   d. the covariance of x and y is on the regression line.

A researcher, working for a large pharmaceutical company, is interested in testing the claim that less than 24% of people who take a new sinus medication receive symptom relief in less than 15 minutes. To test this claim, the researcher collects the following data on a sample of 500 adults and 110 of them receive symptom relief in less than 15 minutes after taking the medication. The following is the data from this study:  Sample size =500 adults The alternative hypothesis is Ha:p<0.24 The test statistic is calculated as z0=−1.05.   Find and interpret the p− value for this hypothesis test.   Use the curve below to help visualize your answer. Select the appropriate test by dragging the blue point to a right-, left- or two-tailed diagram, then set the test statistic on the x-axis to find the p-value.  Based on the p-value, choose the correct interpretation.                       Move the blue dot to choose the appropriate test