Statistical data from a pharmaceutical company
1. A pharmaceutical company conducted a study to evaluate the effectiveness and safety of a new inhaled form of insulin for the treatment of diabetes. A group of 650 diabetics was given the drug twice a day, while another group of 650 diabetics was given an inhaled placebo twice a day. Insulin levels were checked periodically; and the participants were asked to report any adverse side effects (nose bleeds, respiratory infections, nausea, etc.). (14 points)
a. What is the population?
b. What is the sample?
c. Is the study observational or experimental? Explain.
d. What are the independent and dependent variables?
e. For each of the variables identified in part d, what level of measurement was used to obtain data from these variables?
f. Classify the variables identified in part d as either attribute or numerical.
g. What parameter(s) best characterize the effectiveness and safety of the drug?
2. Identify each of the following as examples of nominal, ordinal, discrete, or continuous variables: (6 points)
a. The length of time required for a new epoxy adhesive to harden
b. A telephone poll of consumers asking which cola drink they prefer
c. The number of female students attending a university
d. The finishing order of horses in a race
e. The braking distance of a car on icy pavement
f. The number of crimes in a particular neighborhood per month
3. Based on your lecture readings, identify and describe?in your own words?the four levels of measurement. Provide examples of each. (4 points)
4. Construct a frequency distribution table to organize the following set of quiz scores: (5 points)
2 8 7 3 5 2 1 1 5 9 4 5 6
7 1 2 8 9 1 6 10
5. Construct a grouped frequency distribution for the following 28 scores using a class width of 4. (5 points)
19 18 11 21 19 15 22 25 12 28 20
20 15 17 20 32 14 20 17 30 27 27
22 24 27 14 13 15
6. Identify the sampling technique used to obtain a sample in each of the following. Explain why you chose the sampling technique you did for each. (10 points)
a. Patients at a local hospital are classified according to their age. Then a random sample of 10 patients from each age group is selected.
b. The first 100 people leaving a mall are asked their preferences for fast food
c. A nation is divided into regions based on telephone area codes. A random sample of 10 area codes is selected.
d. Every 10th MP3 player coming off an assembly line is checked for defects
e. Lottery winners are selected using sequences drawn from a random number generator