Observational studies have suggested that low dietary intake or low plasma concentrations of retinol, beta-carotene, or other carotenoids might be associated with increased risk of developing certain types of cancer. However, relatively few studies have investigated the determinants of plasma concentrations of these micronutrients. A cross-sectional study was conducted to investigate the relationship between personal characteristics and dietary factors, and plasma concentrations of retinol, beta-carotene and other carotenoids. Study subjects (N = 315) were patients who had an elective surgical procedure during a three-year period to biopsy or remove a lesion of the lung, colon, breast, skin, ovary or uterus that was found to be non-cancerous. The data from this experiment are in a xlsx file that is part of the In-Class Assignment. Once you have downloaded this file, you can open it using Excel.The following variables are included in the file: AGE (years); SEX (1=Male, 2=Female); SMOKSTAT (1=Never, 2=Former, 3=Current Smoker); QUETELET (BMI, weight/height2); VITUSE (vitamin use; 1=”Yes, fairly often”, 2=”Yes, not often”, 3=”No”); CALORIES (Number of calories consumed per day); FAT (Grams of fat consumed per day); FIBER (Grams of fiber consumed per day); ALCOHOL (Number of alcoholic drinks consumed per week); CHOLESTEROL [Cholesterol consumed (mg per day]; BETADIET [Dietary beta-carotene consumed (mcg per day)]; RETDIET [Dietary retinol consumed (mcg per day)]; BETAPLASMA [Plasma beta-carotene (ng/ml)]; and RETPLASMA [Plasma Retinol (ng/ml)].Analyze the RETPLASMA variable. Use the “Explore Quantitative Data” app to describe the data for each gender.(Attach graphs and descriptive statistics here)Using the mean, standard deviation and sample size, calculate a 95% confidence interval for the mean for males and females. Verify that the 95% confidence interval for the mean for both males and females is correct using the “Inference for a Mean” app. Interpret both confidence intervals. Are these confidence intervals consistent with the graphs that you produced? Do you have any concerns about the confidence intervals that you generated? Explain.Conduct a test for each sex to determine if the variable you chose differs from normal values. Normal values for retinol are 800 ng/ml. Use the same “Inference for a Mean” app.Discuss any concerns you might have with the results of your hypothesis tests.
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