To test μ for an x distribution that is mound-shaped using sample size n ≥ 30, how do you decide whether to use the normal or Student's t distribution?A.If σ is known, use the standard normal distribution. If σ is unknown, use the Student's t distribution with n – 1 degrees of freedom.B. If σ is unknown, use the standard normal distribution. If σ is known, use the Student's t distribution with n – 1 degrees of freedom. C. If σ is known, use the standard normal distribution. If σ is unknown, use the Student's t distribution with n degrees of freedom.D. For large samples we always the standard normal distribution.

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general 4 months ago 9309

A staff member at UF's Wellness Center is interested in seeing if a new stress reduction program will lower employees high blood pressure levels. Twenty people are selected and have their blood pressure measured. Each person then participates in the stress reduction program. One month after the stress reduction program, the blood pressure levels of the employees were measured again. Did the program reduce the average blood pressure level? The 95% confidence interval was (5.6, 10.2). What can we expect will be the p-value for a two sided test using this data?

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general 4 months ago 9309

What is the p-value? -- Researcher Jessie is studying how the fear of going to the dentist affects an adult's actual number of visits to the dentist. She asks a random sample of adults whether or not they fear going to the dentist and also how many times they have gone in the past 10 years. She would like to assess if the average number of visits made by adults who fear going to the dentist (Group 1) is higher than the average number of visits for those who don't have that fear (Group 2), that is, test H0: μ1 = μ2 versus Ha: μ1 > μ2, using a 10% significance level. Her random sample of adults resulted in 14 stating they feared going to the dentist and 31 stated they did not fear going to the dentist. The first sample mean was 1.71 pooled standard errors above the second sample mean. Jessie has asked you to provide a complete sketch of the p-value that she can include in her report. You can use the shiny app in R which will give the exact p-value or make a complete sketch by hand and provide the bounds for the p-value using the T table.2) Jessie also remembers some condition about a normal model required for her two populations of responses. She asks you to check this condition for her. You recall that a QQ plot helps to assess if a population of responses can be considered normally distributed. How many QQ plots do you need to make in this case?None, since the total sample size of 45 adults is large you can just use the CLT.One, for the 45 responses (number of visits) reported by the 45 adults that were surveyed.Two, one for the 14 responses (number of visits) by the adults who fear going to the dentist and one for the 31 responses (number of visits) by the adults who do not fear going to the dentist.

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general 4 months ago 8200

A survey of 61 comma 646 people included several questions about office relationships. Of the​ respondents, 26.5​% reported that bosses scream at employees. Use a 0.05 significance level to test the claim that more than 1 divided by 4 of people say that bosses scream at employees. How is the conclusion affected after learning that the survey is an online survey in which Internet users chose whether to​ respond? Identify the null​ hypothesis, alternative​ hypothesis, test​ statistic, P-value, conclusion about the null​ hypothesis, and final conclusion that addresses the original claim. Use the​ P-value method. Use the normal distribution as an approximation of the binomial distribution.

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general 4 months ago 6104