Answer to Question #167451 in Organic Chemistry for Hafiz Faizal

Question

Reporting summary measures such as the mean, median, and standard deviation has become very common in modern life. Many companies, government agencies will report these descriptive measures of a variable, but they will rarely provide information on the shape of the distribution of that variable. In previous tutorials, you have learned some basic properties of some distributions that can help you to decide if a specific type of distribution is a good fit for a set of data. According to the National Diet and Nutrition Survey: Adults Aged 19 to 64, British men spend an average of 2.15 hours per day in moderate or high intensity physical activity. The standard deviation of these activity times for this sample was 3.59 hours. Can we infer that these activity times could follow a normal distribution? The following may provide an answer.

a. Sketch a normal curve marking the points representing 1, 2, and 3 standard deviations above and below the mean, and calculate the values at these points using a mean of 2.15 hours and standard deviation of 3.59 hours.

b. Examine the curve with your calculations. Explain why it is impossible for this distribution to be normal based on your graph and calculations.

c. Considering the variable being measured, is it more likely that the distribution is skewed to the left or that it is skewed to the right? Explain why.

d. Suppose that the standard deviation for this sample was 0.70 hours instead of 3.59 hours, which make it numerically possible for the distribution to be normal. Again, considering the variable being measured, explain why the normal distribution is still not a logical choice for this distribution.

e. In your opinion, is there any difference between the term statistics and statistic?

Answer 1

a) (-8.62,12.92)

b) it is not for a normal distribution

c) 2.15 hours per day

d)(0.75,3.55)

e)(0.05,4.25)