A researcher examined the effects of mindfulness meditation on stress reduction. The researcher recruited n = 9 participants from a university campus and asked them to participate in a 30-minute mindfulness med- itation session every day for two weeks. Before and after the two-week intervention period, the participants completed the Perceived Stress Scale, a standardized self-report measure of stress levels. The participants' stress scores are shown in this table. participant before meditation after meditation 123456789 15 13 19 13 9 13 11 7 11 5 14 10 16 16 17 18 21 17 On average, by how much did the anxiety scores change from before versus after the two weeks of meditation sessions? Use a related-samples t-test to determine if this change is statistically significant, and calculate the coefficient of determination r². Report your findings as a sentence or two that could be in the Results section of an APA-style research article.

A new vaccination is being used in a laboratory experiment to investigate whether it is effective. There are 273273 subjects in the study. Is there sufficient evidence to determine if vaccination and disease status are related? Vaccination Status Diseased Not Diseased Total Vaccinated 5757 6262 119119 Not Vaccinated 8383 7171 154154 Total 140140 133133 273273 Copy Data Step 6 of 8 :   Find the critical value of the test at the 0.0050.005 level of significance. Round your answer to three decimal places.

Below indicate whether the appropriate test would be an independent t-test, dependent t-test, One-way ANOVA, or z-test. A researcher wants to know if people find baby animals cuter than adult animals. All of the participants in a study are shown 10 pictures of baby animals and 10 pictures of adult animals. They are asked to rate (on a 1 to 10 scale) how cute they think each animal is.

he data on the number of chocolate chips per bag for 42 bags of Chips Ahoy! cookies were obtained by the students in an introductory statistics class at the United States Air Force Academy in response to the Chips Ahoy! 1,000 Chips Challenge sponsored by Nabisco, the makers of Chips Ahoy! Use the data collected by the students to answer the following questions and to conduct the analyses required in each part. They found ¯xx¯ = 1261.6 and s = 117.6 a. Determine a 95% confidence interval for the mean number of chips per bag for all bags of Chips Ahoy! cookies. ≤μ≤≤μ≤  b. Interpret your result in words.    c. Can you conclude that the average bag of Chips Ahoy! Cookies contain at least 1000 chocolate chips?    yes no

O Macmillan Learning Many young men in North America and Europe (but not in Asia) tend to think they need more muscle to be attractive. One study presented 200 young American men with 100 images of men with various levels of muscle. Researchers measure level of muscle in kilograms per square meter of body surface area (kg/m²). Typical young men have about 20 kg/m². Each subject chose two images, one that represented his own level of body muscle and one that he thought represented "what women prefer." The mean gap between self-image and "what women prefer" was 2.35 kg/m². Suppose that the "muscle gap" in the population of all young men has a Normal distribution with standard deviation 2.5 kg/m². Give a 90% confidence interval for the mean amount of muscle young men think they should add to be attractive to women. (They are wrong: women actually prefer a level close to that of typical men.) Give your answers to four decimal places. lower limit: upper limit: Chi-Fu Jeffrey Yang, Peter…

Many people take ginkgo supplements advertised to improve memory. Are these over-thecounter supplements effective? In a study, elderly adults were assigned to the treatment group or control group. The 104 participants who were assigned to the treatment group took 40 mg of ginkgo 3 times a day for 6 weeks. The 115 participants assigned to the control group took a placebo pill 3 times a day for 6 weeks. At the end of 6 weeks, the Wechsler Memory Scale was administered. Higher scores indicate better memory function. Summary values are given in thefollowing table:                N               x              sGinkgo 104           5.7         0.6Placebo 115         5.5          0.5a) Based on these results, is there evidence that taking 40mg of ginkgo 3 times a day is effective in increasing mean performance on the Wechsler Memory Scale? b) Write a brief report on your findings