Select Split Transform

1. Select only quiz1, gpa & final
and view few top rows
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select = c(…
c is for combine

2. Select only final > 60
and view few top rows
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2
Mathematical argument

3. Compare box plots of final of all 105
observations and with final>60
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> boxplot(grades$final,
main = "Box Plot of final",
col="red")

4. Compare correlation between final and gpa in all
105 observations and in subset final > 60
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5. Create subset of only WHITES (ethnicity = 4) and view
few top rows and make box plot of final
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6. Create subset of only HISPANICS (ethnicity = 5) and
view few top rows and make box plot of final
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7. Compare box plots of final for WHITES and
HISPANIC
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8. Transform final with square root and
recode as new variable
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c
c
c

9. Compare Histograms of final and
sqrtfinal
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Final: skewness = -0.33 ; kurtosis = -0.42
Sqrtfinal: skewness = -0.48 ; kurtosis = -0.17

10. Convert final into two categories of final
[one, <60 and second >60, 60 will fall in > 60]
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11. Dr Vinod on Subset & Transformation
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Convert final into two categories of final
[one, <60 and second >60]

12. Convert final into categories with increment of 5
[40-45=1, 46-50=2, 51-55=3, 56-60=4, 61-65=5, 66-70=6, 71-75=7]
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13. Converting ethnicity into two categories
[category 1= 1, 3& 5; category 2 = 2 & 4
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14. Take out 20% observations randomly from the file
grades
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15. All 20% cases [21#]
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16. Case numbers are known by sam command
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