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.

The Army reports that the distribution of head circumferences among male soldiers is approximately normal with μ =22.8 inches and σ = 1.1 inches. What is the circumference of a soldier whose head is 2.34 standard deviations above the mean?

Reports on a student's test score such as the SAT or a child's height or weight usually give the percentile as well as the actual value of the variable. The percentile is just the cumulative proportion stated as a percent: the percent of all values of the variable that were lower than this one. The upper arm lengths of females in the United States are approximately Normal with mean 35.735.7 cm and standard deviation 2.12.1 cm, and those for males are approximately Normal with mean 39.139.1 and standard deviation 2.32.3 cm. Larry, a 6060‑year‑old male in the United States, has a upper arm length of 37.837.8 cm. What is his percentile? (Enter your answer rounded to two decimal places.)

A successful basketball player has a height of 6 feet 11 ​inches, or 211 cm. Based on statistics from a data​ set, his height converts to the z score of 5.17. How many standard deviations is his height above the​ mean?

In the class of 2019, more than 1.6 million students took the SAT. The distribution of scores on the math section (out of 800) is approximately normal with a mean of 528 and standard deviation of 117.  What proportion of students earned scores between 500 and 600 on the SAT math test?

15

In a study of facial behavior, people in a control group are timed for eye contact for a 5 minute period. They are normally distributed with a mean of 177 seconds and a standard deviation of 53 seconds. I need to find the percentage of times within 53 seconds of the mean of 177 seconds and round it one decimal place if needed.

Low-density lipoprotein, or LDL, is the main source of cholesterol buildup and blockage in the arteries. This is why LDL is known as "bad cholesterol." LDL is measured in milligrams per deciliter of blood, or mg/dL. In a population of adults at risk for cardiovascular problems, the distribution of LDL levels is normal, with a mean of 123 mg/dL and a standard deviation of 41 mg/dL. If an individual's LDL is at least 1 standard deviation or more above the mean, he or she will be monitored carefully by a doctor. What percentage of individuals from this population will have LDL levels 1 or more standard deviations above the mean? Use the 68–95–99.7 rule. (Enter your exact answer as a whole number.) percentage %