STAT 3900/4950 HOMEWORK/LAB ONE Dr. Fan
Topics: Descriptive Statistics and t Tests
Reading assignment: STAT 3900 Units 5, 6
STAT 4950 Chapter 2 and Chapter 6 (A, B, E, F)
STAT 4950 students must provide SAS code for each part
Question 1: Ann wants to describe the demographic characteristics of a sample of 25 individuals who completed a large-scale survey. She has demographic data (on the second page) on the participants’ gender (2 categories), educational level (4 categories), marital status (3 categories), and community population size (8 categories). The data is attached in the appendix.
a. Conduct a frequency analysis on each of the gender and marital status variables. From the output, identify the following:
i. Percent of men
ii. Mode for marital status
iii. Frequency of divorced people in the sample
b. Draw a clustered bar chart for the gender and educational level. Discuss what you observe from the chart.
c. Create a frequency table to summarize the data on the educational level variable.
d. Create a bar chart and a pie chart for the community population variable. Which chart is more appropriate for this variable? Explain your choice.
e. Write a summary section describing the participants in Ann’s sample.
Question 2: We have recorded the following data from an experiment:
SUBJECT / DOSE / REACT / LIVER_WT1 / 1 / 5.4 / 10.2
2 / 1 / 5.9 / 9.8
3 / 1 / 4.8 / 12.2
4 / 1 / 6.9 / 11.8
5 / 1 / 15.8 / 10.9
6 / 2 / 4.9 / 13.8
7 / 2 / 5.0 / 12.0
8 / 2 / 6.7 / 10.5
9 / 2 / 18.2 / 11.9
10 / 2 / 5.5 / 9.9
a. Draw histograms, normal probability plots and boxplots for REACT, and test its distribution for normality. In addition, choose TWO sets of the base intervals, one of 3 intervals and the other of 5 intervals, to draw histogram and see if the overall pattern of histogram changes accordingly.
b. We would like to compare the response REACT under different doses. Can we conclude that the mean REACT is significantly different between DOSE 1 and DOSE 2? We will answer the question by doing the following:
i. Draw a stem-and-leaf plot of REACT for DOSE 1 and another one for REACT for DOSE 2.
ii. Can we conduct a t test to answer this question? If we can, conduct the t test; if not, conduct a non-parametric test. (Hint: What are the required data conditions to conduct t tests?)
iii. Report the test conclusion in the context of the situation.
c. Repeat b. for LIVE_WT (DOSE 1 vs. DOSE 2).
Ann’s Data:
Subject Gender Educational Marital Population
Level status size
------
1 2 4 2 2
2 1 4 3 2
3 1 3 1 2
4 1 1 2 8
5 2 2 2 3
6 1 1 1 6
7 1 3 2 6
8 1 4 3 5
9 1 1 2 8
10 2 2 1 7
11 2 3 2 8
12 2 4 2 5
13 1 1 2 7
14 1 3 3 6
15 2 1 1 4
16 1 4 1 4
17 2 3 2 1
18 1 2 2 2
19 2 3 2 5
20 2 3 1 8
21 2 4 3 6
22 1 1 1 6
23 2 2 1 3
24 2 3 1 3
25 1 4 3 6
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Gender 1: men, 2: women
Educational Level 1: below high school, 2: high school graduates,
3: college graduates, 4: postgraduates
Marital status 1: married, 2: divorced, 3: never married
Population size 1: > 100,000, 2: 50,001-100,000, 3: 25,001-50,000,
4: 10,001-25,000, 5: 5,001-10,000, 6: 1001-5000,
7: 501-1000, 8: < = 500
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