9.7 Classes on Fridays. A professor is concerned that not enough courses at his college hold class meetings on Fridays. After speaking with administrators, the professor finds out that 15% of courses have class meetings on Fridays. At this school, classes meet on either Monday-Wednesday-Friday or Tuesday-Thursday and do not meet on Saturday or Sunday.
(a) The 15% figure is about right because Friday is one of seven days of the week.
(b) The 15% figure is low because it is less than 20%, and Friday is one of five days on which classes meet.
(c) We cannot make a decision about the 15% figure because we do not know how courses are divided among teaching days (e.g., Monday-Wednesday-Friday or Tuesday-Thursday).
(d) The 15% figure is high because students tend to skip classes on Fridays.