research center claims that at least 23​% of adults in a certain country think that their taxes will be audited. In a random sample of 900 adults in that country in a recent​ year, 18​% say they are concerned that their taxes will be audited. At α = 0.01​, is there enough evidence to reject the​ center's claim?  Identify the critical​ value(s) for this test.   Zo =?   Find the standardized test statistic z. Z=?

Is narcissism a more common personality trait today than it was a few decades ago?  It is known that the mean population score on the Narcissistic Personality Inventory (NPI) for students attending University of South Alabama around 20 years ago was μ= 15 (Twenge, 2010).  Interested in the narcissism levels of students in the year 2020, a researcher administers the NPI to a random sample of 25 University of Alabama sophomores this Spring term. The mean NPI score from the researcher’s sample of sophomores is M = 16.5, with s = 3.4. 1. Write the null and alternative hypotheses in symbols. Possible symbols for your answer: H0, H1, μ, M, σ. 2. Calculate the standard error.  3. Find the critical value for the test statistic, assuming alpha = .05 (Use largest [i.e., most conservative] value if exact value not given in the chart)  a) 2.064 b) 1.96 c) 1.98 d) 2.000

Bone mineral density (BMD) is a measure of bone strength. Studies show that BMD declines after age 45. The impact of exercise may increase BMD. A random sample of 59 women between the ages of 41 and 45 with no major health problems were studied. The women were classified into one of two groups based upon their level of exercise activity: walking women and sedentary women. The 39 women who walked regularly had a mean BMD of 5.96 with a standard deviation of 1.22. The 20 women who are sedentary had a mean BMD of 4.41 with a standard deviation of 1.02. Which of the following inference procedures could be used to estimate the difference in the mean BMD for these two types of women

The mean potassium content of a popular sports drink is listed as 132 mg in a 32-oz bottle. Analysis of 24 bottles indicates a sample mean of 131.2 mg. (a) State the hypotheses for a two-tailed test of the claimed potassium content.. a. Ho: μ= 132 mg vs. H₁: b. He: ≤132 mg vs. H₁: c. He: ≥132 mg vs. H₁: Oa Ob Oc (b) Assuming a known standard deviation of 2.1 mg, calculate the z test statistic to test the manufacturer's claim. (Round your answer to 2 decimal places. A negative value should be indicated by a minus sign.) Test statistic 132 mg >132 mg <132 mg (c) At the 2 percent level of significance (a = .02) does the sample contradict the manufacturer's claim? Decision Rule: Reject Ho

In a test of the effectiveness of garlic for lowering cholesterol, 64 subjects were treated with raw garlic. Cholesterol levels were measured before and after the treatment. The changes (before minus after) in their levels of LDL cholesterol (in mg/dL) have a mean of 0.2 and a standard deviation of 1.81. Use a 0.10 significance level to test the claim that with garlic treatment, the mean change in LDL cholesterol is greater than 0. What do the results suggest about the effectiveness of the garlic treatment? Assume that a simple random sample has been selected. Identify the null and alternative hypotheses, test statistic, P-value, and state the final conclusion that addresses the original claim. What are the null and alternative hypotheses? O A. Ho: H>0 mg/dL O B. Ho: H=0 mg/dL H:H0 mg/dL Determine the test statistic. (Round to two decimal places as needed.)

In a test of the effectiveness of garlic for lowering​ cholesterol, 49 subjects were treated with raw garlic. Cholesterol levels were measured before and after the treatment. The changes​ (before minus​ after) in their levels of LDL cholesterol​ (in mg/dL) have a mean of 0.8 and a standard deviation of 2.04. Use a 0.10 significance level to test the claim that with garlic​ treatment, the mean change in LDL cholesterol is greater than 0. What do the results suggest about the effectiveness of the garlic​ treatment? Assume that a simple random sample has been selected. Identify the null and alternative​ hypotheses, test​ statistic, P-value, and state the final conclusion that addresses the original claim.

In a test of the effectiveness of garlic for lowering cholesterol, 81 subjects were treated with raw garlic. Cholesterol levels were measured before and after the treatment. The changes (before minus after) in their levels of LDL cholesterol (in mg/dL) have a mean of 0.2 and a standard deviation of 17.2. Use a 0.05 significance level to test the claim that with garlic treatment, the mean change in LDL cholesterol is greater than 0. What do the results suggest about the effectiveness of the garlic treatment? Assume that a simple random sample has been selected. Identify the null and alternative hypotheses, test statistic, P-value, and state the final conclusion that addresses the original claim. What are the null and alternative hypotheses? Ο Α. Hρ: μ=0 mg/dL O B. Ho: µ=0 mg/dL H;: u#0 mg/dL H,: µ>0 mg/dL O C . H: μ=0 mg/dL O D. Ho: µ>0 mg/dL H;: µ<0 mg/dL H,:µ<0 mg/dL Determine the test statistic. (Round to two decimal places as needed.) Determine the P-value, (Round to three decimal…

In a test of the effectiveness of garlic for lowering​ cholesterol, 64 subjects were treated with raw garlic. Cholesterol levels were measured before and after the treatment. The changes​ (before minus​ after) in their levels of LDL cholesterol​ (in mg/dL) have a mean of 0.6 and a standard deviation of 1.92. Use a 0.05 significance level to test the claim that with garlic​ treatment, the mean change in LDL cholesterol is greater than 0. What do the results suggest about the effectiveness of the garlic​ treatment? Assume that a simple random sample has been selected. Identify the null and alternative​ hypotheses, test​ statistic, P-value, and state the final conclusion that addresses the original claim.   What are the null and alternative​ hypotheses?