Journal of Research in Innovative Teaching - National University

If the mean number of visits was assumed to be 2.6 and in fact it is greater, the office will be
overcrowded, which is not good for the business. On the other hand, if the mean of 3.2 visits was
assumed and in fact it is smaller, there will be extra space, which is not as bad as overcrowding.
Therefore, the dentist must use the upper limit: 3.2 visits per year per capita.
(B) What amount of money must be taken into account to figure out projected income
This time, a prudent answer will be the lower limit, or $415.
Example 2. A student association at a college figured out that 7.5% to 9.5% of all students
usually join it. If the present number of students at the college is 13,000, how many booklets
should the association print in order to accommodate all prospective members
The given confidence interval is (0.075, 0.095). The safer decision would be 13,000*0.095 =
1,235 booklets. It is better to have extra copies than run out of them.
Large vs. small samples. The authors of some textbooks (for instance, Larsen 2006) use the
criterion of large and small samples (n > 30 or n < 30 respectively). This allows replacing the
population standard deviation with the sample standard deviation for constructing confidence
intervals and hypothesis testing if a sample is large. Such technique is not accurate, but it results
in a 6% error for n = 30 and 4% error for n = 50, which is acceptable for inferential statistics.
Other authors, including Triola (2008), stand on more strict positions and do not use such
classification; instead, they consider the cases of known versus unknown population standard
deviation. It is obvious that in reality this population parameter is hardly known in advance. In
case it is unknown, the student’s distribution must be used instead of the normal. That is
absolutely correct and not too complicated. There is only one obstacle: a 4-week course does not
leave a chance to cover the student’s distribution. Therefore, we have no other choice but
consider only large samples, apply the approximate technique, and use the normal distribution.
Homework Assignments
The students must complete four homework assignments. It was already mentioned that these
assignments consist mostly of word problems rather than just exercises. The answers to the odd
problems can be found in the book, while the answers to the even problems are given on each
assignment page. This way a student can always check the answer to a problem and ask for help
if necessary. Showing all work on each problem involving calculations is a strict requirement; a
bare answer earns no credit.
Setting deadlines for homework assignments needs careful balancing. In almost every
class, a couple of students receive their textbooks with delay and cannot complete the first
assignment on time. Therefore, giving one or two day of slack on the first assignment deadline
may help them catch up with the class. The same thing can be recommended about assignments
#2 and #4, since students have to do the homework and prepare for the exam at the same time.
Threaded Discussion
It is generally known that threaded discussion is an important element of online education.
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