Macao Polytechnic Institute
School of Business
Bachelor of Art in Public Relation Programme
Semester, Year 2012/13
Math211521122, Assignment III
P1103808 Leong Lai Nga, Delia
Write down your full name and student ID on the first page. Handin your assignment on or before nd
the day of 2
1. Blood Glucose Level
. In the article "Drinking Glucose Improves Listening Span in Students Who Miss Breakfast" (
, Vol. 43, No. 2, pp.201207), authors N. Morris
and P. Sarll explore the relationship between students who skip breakfast and their performance on a number of cognitive tasks. According to their findings, blood glucose levels in the morning, after a 9hour fast, have a mean of 4.60 mmol
with a standard deviation of 0.16
is an abbreviation of millimoles/liter, which is the world standard unit for measuring glucose in blood).
. Determine the sampling distribution of the sample mean for samples of size 60. b
part (a) for samples of size 120.
assume that the blood glucose levels are normally distributed to answer parts (a) and (b)? Explain your answer.
. Approximately normally distributed with mean 4.60 and standard deviation 0.021. b
. Approximately normally distributed with mean 4.60 and standard deviation 0.015. c
. No, because, in each case, the sample size exceeds 30.
2. Diamond Pricing
. In a Singapore edition of Business Times, diamond pricing was explored. The price of a diamond is based on the diamond's weight, color, and clarity. A simple random sample of 18 onehalf carat diamonds had the following prices, in dollars. 1676
. Apply the tinterval procedure to these data to find a 90% confidence interval for the mean price of all onehalf carat diamonds. Interpret your result. ( Note
: = $1964.7 and
. Obtain a normal probability plot of the data.
. Based on your graphs from part (b), is it reasonable to apply the tinterval procedure as you did in part (a)? Explain your answer.
. $1880.1 to $2049.4. We can be 90% confident that the mean price of all onehalf carat diamonds is somewhere between $1880.1 and $2049.4.
. This one is a tough call, but using the
interval procedure is probably reasonable. The sample size is moderate and, although the boxplot shows a potential outlier, the other three plots suggest that the potential outlier may, in fact, not be an outlier. Furthermore, the normal probability plot is roughly linear.
The following graph portrays the decision criterion for a hypothesis test about a population mean,
. The null hypothesis for the test is H
, and the test statistic is
The curve shown in the graph reveals the implications of the decision criterion if in fact the null hypothesis is true.
. rejection region.
. nonrejection region.
. critical value(s).
. significance level.
. Classify the hypothesis test as two tailed, left tailed, or right tailed. Ans
. The U.S. Department of Agriculture reports in
Prices, and Expenditures
that the average American consumed 30.0 lb of cheese in 2001. The following table provides last year's cheese consumption, in pounds, for 35 randomly selected Americans.
Please join StudyMode to read the full document