1. At a university, the distribution of undergraduate students by class standing is:
Freshman 29%
Sophomore 27%
Junior 25%
Senior 19%
Assume these fractions are exact.
2. You select a simple random sample of 206 students --- at least, you think it's random. In your sample, the numbers of students by class is:
Freshman 54
Sophomore 66
Junior 56
Senior 30
Carry out a Chi-Square test to decide whether it is reasonable to believe that these are really random.
3. An event threatened the lives of some people, who were themselves divided into three categories; here were the results:
DIED SURVIVED
Category I 117 187
Category II 163 112
Category III 526 186
unknown Cat. 13 19
(TOTAL) 819 504
Is it possible that the row variable and column variable are independent, except for random variation? Carry out a two-way chi-square test. Determine: (a) the entries that would appear in the cells if the variables were independent; (b) the z-statistic for each cell; (c) the chi-square statistic; (d) the result of the test, whether in the form of a p-value or a comparison to some chi-square critical value.
3. Computer exercise: In this exercise you will open JMP, carry out a comparison-of-means test, copy the results onto a PowerPoint slide, and email me the result.
a. Open the PowerPoint file called "11template.ppt" from the class website.
b. Open JMP 7.
c. Open the data table "jan-dec.JMP" from the class web site.
d. Making sure the data table is selected, from the "Analyze" menu, select "Fit Y by X".
e. Make Column 1 be the response variable ("Y") and make Column 2 be the factor variable ("X").
f. Click "OK" to create a new report file containing a simple graphic.
g. From the red-triangle menu on the graphic, select "T test". An additional section should appear in the report, comparing the means for the "jan" group and the "dec" group.
h. Select the "T test" section of the report. (This is tricky. Use the "selection tool" --- a white cross --- in the toolbar.)
i. Copy the "T-test" section of the report, and paste it anywhere on the PowerPoint slide. Then move it into a better position so that it becomes readable. Clean it up or edit it in other ways if you like.
Attachment:- Assignment.rar