Confidence Intervals - Statistics Project Example

Week 4 Assignment: Confidence Interval Male and Female Body Mass Index (BMI) Week 4 Assignment: Confidence Interval The body mass index (BMI) is a measure for human body shape based on an individuals mass and height. It is a simple index of weight-for-height that is commonly used to classify underweight, overweight and obesity in adults (BMI classification, 2013). The body mass index is defined as the individual’s body mass divided by the square of their height and can be calculated using below formulas: A data set is collected for male and female for their age, weight and height, and BMI is calculated.

The data set is attached in Appendix A. This paper will analyse the male and female BMI based on confidence interval (inferential statistics). In addition, this paper will also compare male and female BMI values with the national averages and with the International Classification of adult underweight, overweight and obesity according to BMI.99% Confidence Interval Estimate of the Mean Body Mass Index for Men The average mean body index for men is about 27.62 (SD = 10.88). The margin of error (half width) for a 99% confidence is about 4.

66 (See Appendix B for calculation). The 99% lower and upper confidence limits of BMI for men are Lower Confidence Limit = = 27.62 – 4.66 = 22.96Upper Confidence Limit = = 27.62 + 4.66 = 32.28Therefore, the 99% confidence interval for the mean body mass index for men is between 22.96 and 32.28. Thus, there is 99% chance that the mean body mass index for men falls in the interval (22.96, 32.28). 99% Confidence Interval Estimate of the Mean Body Mass Index for Women The average mean body index for women is about (26.70 SD = 6.93).

The margin of error for a 99% confidence is about 2.97 (See Appendix B for calculation). The 99% lower and upper confidence limits of BMI for women are Lower Confidence Limit = = 26.70 – 2.97 = 23.73Upper Confidence Limit = = 26.70 + 2.97 = 29.67Therefore, the 99% confidence interval for the mean body mass index for women is between 23.73 and 29.67. Thus, there is 99% chance that the mean body mass index for women falls in the interval (23.73, 29.67). Comparison of Men and Women Body Mass IndexIt is known that men have a mean weight that is greater than the mean weight for women, and the mean height of men is greater than the mean height of women.

The results suggest that men (M = 27.62, SD = 10.88) also have a mean body mass index that is greater than the mean body mass index of women (M = 26.70, SD = 6.93). However, the 99% confidence interval for the mean body mass index for women (23.73, 29.67) is narrower as compared to the 99% confidence interval for the mean body mass index for men (22.96, 32.28). Thus, the mean body mass index for women is less variable as compared to the mean body mass index for men.Comparison of Men and Women BMI Values with the International Classification of AdultThe U.S. National Institutes of Health and the Centers for Disease Control and Prevention uses World Health Organization guidelines for classification of adult underweight, overweight and obesity according to BMI.

The Table 1 shows the International Classification of adult underweight, overweight and obesity according to BMI (BMI classification, 2013).Table 1: The International Classification of adult underweight, overweight and obesity according to BMIClassificationCut-off PointsUnderweight