Calculate the number of participants needed to detect a difference of 1 unit in mean balance score with 80% power.

Question

Consider a cohort study to compare the mortality rate of myocardial infarction (MI) in men with sedentary work (exposed group) to men with physically active work (unexposed). If in the exposed, there were 36,000 person (man) years of observation and 126 deaths whereas the unexposed had 24,000 man-years of observation and 44 deaths. Compute the following a) Mortality rate in each cohort? b) What is the relative risk of dying, comparing these 2 groups? c) What is the attributable risk of sedentary work? d) What is the attributable benefit of physical activity? e) If we assume that MI is associated with the mortality in this cohort (causality), what proportion of the disease in the higher group is potentially preventable?

Answer 1

Question

Features Features Normal distribution is characterized by two parameters, mean (µ) and standard deviation (σ). When graphed, the mean represents the center of the bell curve and the graph is perfectly symmetric about the center. The mean, median, and mode are all equal for a normal distribution. The standard deviation measures the data's spread from the center. The higher the standard deviation, the more the data is spread out and the flatter the bell curve looks. Variance is another commonly used measure of the spread of the distribution and is equal to the square of the standard deviation.

Chapter 8, Problem 65P

To determine

Calculate the number of participants needed to detect a difference of 1 unit in mean balance score with 80% power.

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Consider a cohort study to compare the mortality rate of myocardial infarction (MI) in men with sedentary work (exposed group) to men with physically active work (unexposed). If in the exposed, there were 36,000 person (man) years of observation and 126 deaths whereas the unexposed had 24,000 man-years of observation and 44 deaths. Compute the following a) Mortality rate in each cohort? b) What is the relative risk of dying, comparing these 2 groups? c) What is the attributable risk of sedentary work? d) What is the attributable benefit of physical activity? e) If we assume that MI is associated with the mortality in this cohort (causality), what proportion of the disease in the higher group is potentially preventable?

A fast-food chain decided to carry out an experiment to assess the influence of advertising expenditure on sales. Different relative changes in advertising expenditure, compared to the previous year, were made in eight regions of the country, and resulting changes in sales levels were observed the accompanying table shows the results. Increase in advertising expenditure (%) 0 5 15 20 25 30 35 40 Increase in sales (%) 5 10 18 25 35 50 60 65 Determine the value of ∑X, ∑X2, ∑Y, ∑Y2, ∑XY. Where X represent independent variable and Y for dependent variable. Determine and interpret the coefficient of correlation between the two variables. Determine the value of regressions coefficients and write down the simple linear regression model.…

A fast-food chain decided to carry out an experiment to assess the influence of advertising expenditure on sales. Different relative changes in advertising expenditure, compared to the previous year, were made in eight regions of the country, and resulting changes in sales levels were observed the accompanying table shows the results. Increase in advertising expenditure (%) 0 5 15 20 25 30 35 40 Increase in sales (%) 5 10 18 25 35 50 60 65 Determine the value of ∑X, ∑X2, ∑Y, ∑Y2, ∑XY. Where X represent independent variable and Y for dependent variable. Determine and interpret the coefficient of correlation between the two variables. Determine the value of regressions coefficients and write down the simple linear regression model. Test the validity of the model…

Answer 2

Question

Features Features Normal distribution is characterized by two parameters, mean (µ) and standard deviation (σ). When graphed, the mean represents the center of the bell curve and the graph is perfectly symmetric about the center. The mean, median, and mode are all equal for a normal distribution. The standard deviation measures the data's spread from the center. The higher the standard deviation, the more the data is spread out and the flatter the bell curve looks. Variance is another commonly used measure of the spread of the distribution and is equal to the square of the standard deviation.

Chapter 8, Problem 65P

To determine

Calculate the number of participants needed to detect a difference of 1 unit in mean balance score with 80% power.

Expert Solution & Answer

Trending nowThis is a popular solution!

See solution

Check out sample textbook solution

Answer 3

Question

Features Features Normal distribution is characterized by two parameters, mean (µ) and standard deviation (σ). When graphed, the mean represents the center of the bell curve and the graph is perfectly symmetric about the center. The mean, median, and mode are all equal for a normal distribution. The standard deviation measures the data's spread from the center. The higher the standard deviation, the more the data is spread out and the flatter the bell curve looks. Variance is another commonly used measure of the spread of the distribution and is equal to the square of the standard deviation.

Chapter 8, Problem 65P

To determine

Calculate the number of participants needed to detect a difference of 1 unit in mean balance score with 80% power.

Expert Solution & Answer

Trending nowThis is a popular solution!

See solution

Check out sample textbook solution

Answer 4

Question

Features Features Normal distribution is characterized by two parameters, mean (µ) and standard deviation (σ). When graphed, the mean represents the center of the bell curve and the graph is perfectly symmetric about the center. The mean, median, and mode are all equal for a normal distribution. The standard deviation measures the data's spread from the center. The higher the standard deviation, the more the data is spread out and the flatter the bell curve looks. Variance is another commonly used measure of the spread of the distribution and is equal to the square of the standard deviation.

Chapter 8, Problem 65P

To determine