confidence interval estimate of the mean net change in LDL cholesterol after the garlic treatment. What does the confidence interval suggest about the effectiveness of garlic in reducing LDL​ cholesterol?

The effects of an iron supplement in increasing hemoglobin levels is being clinically tested on a group of 160 patients suffering from anemia (low iron). Combined with a specific dietary plan, those using the supplement experienced an average hemoglobin increase of 6.8 g/dL. It is known from previous clinical trials that the standard deviation of the increase in hemoglobin levels as a result of using the supplement is 2.9 g/dL. Calculate the margin of error and construct the 99% confidence interval for the true mean hemoglobin-level increase caused by the supplement. 1.  E=  Round to 3 significant digits   2. ______ < μ <_____ g/dL   Round to 2 decimal places

A laboratory tested 25 chicken eggs and found that the mean amount of cholesterol was 225 milligrams with s=13.4 milligrams. Construct a 95 percent confidence interval for the mean cholesterol content of all such eggs.

Arsenic occurs naturally in some ground water and can be toxic. A mean arsenic level of μ=9 parts per billion (ppb) is considered safe for agricultural use. A well in San Bernardino County is used to water strawberry crops. This well is tested on a regular basis for arsenic. A random sample of 42 tests gave a sample mean of 8.5 ppb arsenic, with a sample standard deviation of 2.1 ppb. Does this information indicate that the mean level of arsenic in this well is less than μ=9ppb? Use α=0.005 What is the level of significance? State the null and alternate hypotheses. H0:H0:? σ p μ χ  Select an answer < > = ≠  ppbH1:H1:? μ p χ σ  Select an answer > = ≠ <  ppb   What is the value of the test statistic? (Round your answer to two decimal places.)Find the P-value. (Round your answer to four decimal places.)

Arsenic occurs naturally in some ground water and can be toxic. A mean arsenic level of μ=9μ=9 parts per billion (ppb) is considered safe for agricultural use. A well in San Bernardino County is used to water strawberry crops. This well is tested on a regular basis for arsenic. A random sample of 46 tests gave a sample mean of 8 ppb arsenic, with a sample standard deviation of 5.4 ppb. Does this information indicate that the mean level of arsenic in this well is different from μ=9μ=9 ppb? Use α=0.05α=0.05What is the level of significance? State the null and alternate hypotheses. H0:H0:? χ p σ μ  Select an answer < ≠ > =  ppbH1:H1:? σ p χ μ  Select an answer ≠ > < =  ppbWhat sampling distribution will you use? Explain the rationale for you choice of sampling distribution. The Student's t, since we have a simple random sample that is large and σσ is known. The Student's t, since we have a simple random sample that is large. The standard normal, since we have a simple random…

A test score of 45 has an equivalent standard score (z-score) of 1.6. If the mean test score is 39, what is the standard deviation?

The amount of time a certain brand of light bulb lasts is normally distributed with a mean of 1400 hours and a standard deviation of 50 hours. Using the empirical rule, determine what interval of hours represents the lifespan of the middle 68% of light bulbs.

Blood coagulation levels for obese patients have a mean of 10 seconds with a standard deviation of 2. A researcher thinks that a diet high in raw vegetables and fruits will have a positive or negative effect on the cholesterol levels. A sample of 30 patients who have tried the diet have a mean coagulation level of 12. Test the hypothesis with 5% significance level that the raw vegetables and fruits had an effect. ?

A random sample of 36 patients with arthritis took the drug for three months. Blood tests showed that x=8.8 with sample standard deviation a=3.3. Use a 5% level of significance to test the claim that the drug has changed the mean pH level of the blood.

The tensile strength of paper using 5% hardwood and 10% hardwood are to be compared. A random sample of 41 sheets made from 5% hardwood had an average tensile strength of 1.52 lbs. with a standard deviation of 0.33 lbs. A random sample of 61 sheets made from 10% hardwood had an average tensile strength of 1.88 lbs. with a standard deviation of 0.42 lbs. Can we conclude the average tensile strength is the same for the two types of paper? Use 5% significance and p-values. Part 1) Conduct the test using the assumption that the sample standard deviations are the same as the population standard deviations. Part 2) Conduct the test using the assumption that the population standard deviations are unknown but equal (you also must assume a normal population here). Part 3) Conduct the test with only the assumption that we have simple random samples from normal populations. May you please explain which stat test you used on your calculator and why. Thank you very much for your help!