Question: In each experiment, determine whether the data are obtained independently or are paired. If the data are independent, indicate the two distinct populations. If the data are paired, indicate the common characteristic.
a. A random sample of soccer players on the Brazil national team and a random sample of soccer players on the Argentina national team was obtained. The amount of time (in minutes) each played during a World Cup match was obtained. The data will be used to determine whether the mean time is different for the two teams.
b. A random sample of bananas from Columbia and Costa Rica was obtained. The amount of fiber in the peel of each banana was carefully measured and recorded. The data will be used to determine whether there is a difference in the mean amount of fiber in the banana peel by country.
c. A new stent has been designed for use in patients with diseased arteries. A random sample of patients in need of a stent was selected. The intrasaccular pressure of each was carefully measured, and then a stent was surgically placed in the diseased artery. The intrasaccular pressure was measured again following surgery. The data will be used to determine whether the stent placement reduced intrasaccular pressure.
d. An automobile manufacturer claims that using a lighter weight engine oil can actually increase a car's miles per gallon (of gasoline). A random sample of cars (and drivers) was selected, all who currently use a heavy weight oil in their engines. The miles per gallon for each car was recorded. The engine oil was drained, a lighter weight oil was used, and the miles per gallon was recorded again. The data will be used to determine if the mean miles per gallon has increased.
e. A new process has been developed that theoretically improves the nutritional value of barley for use in fish feed.* A random sample of traditional barley and another random sample of the new barley was obtained. The percentage of protein in each grain was carefully measured. The data will be used to determine whether the new barley has a greater mean percentage of protein.