seminar 20
DESCRIPTION
Seminar 20. By Colin Sundwick. SAT Math Scores. Variable N N* Mean SE Mean StDev Minimum Q1 Median Q3 Math 390 56 610.44 3.65 72.14 400.00 560.00 610.00 660.00 μ= 610.44 σ = 72.14. The shape is fairly normal. - PowerPoint PPT PresentationTRANSCRIPT
ByColin Sundwick
SAT Math ScoresVariable N N* Mean SE Mean StDev Minimum Q1 Median Q3Math 390 56 610.44 3.65 72.14 400.00 560.00 610.00 660.00
μ= 610.44σ= 72.14
The shape is fairly normal.
Random Small SamplesNext, I randomly
sampled 10 rows of math SAT scores 20 times and recorded the mean of each small sample.
57 25858 55859 560 238861 5862 126663 17646566 2
Stem-and-Leaf PlotCenter- 608Spread- 23.32Shape- fairly normal
except for one high value.
57 25858 55859 560 238861 5862 126663 17646566 2
Random LARGE SamplesNext, I did the same
thing, except with 40 rows instead of 10.
58 859 459 5960 060 789961 013461 56862 00462 5
Stem-and-Lead PlotCenter- 610.5Spread- 10.31Shape- pretty
normal
58 859 459 5960 060 789961 013461 56862 00462 5
How do they compare? Samples of 10 Samples of 40Center- 608Spread- 90Shape- fairly normal
with one apparent outlier, even though the 1.5 x IQR rule doesn’t classify it as one.
Center- 609.5Spread- 37Shape- normal
Boxplots
Wages Earned Variable N N* Mean SE Mean StDev Minimum Q1 Median
Q3 Earned 446 0 3.776 0.308 6.503 0.000 1.000 2.000
4.000
μ = 3.776σ= 6.503
The graph is clearly skewed right
Random Small SamplesNext, I randomly sampled
10 rows of wages earned 20 times and recorded the mean of each small sample.
1 672 013442 773 043 7994 34 65 35 666 577 8
Stem-and-Leaf PlotCenter- 3.2Spread- 1.68Shape- skewed right
1 672 013442 773 043 7994 34 65 35 666 577 8
Random Large SamplesNext, I did the same
thing, except with 40 rows instead of 10.
2 12 5663 0012233 57784 002234 8
Stem-and-Leaf PlotCenter- 3.4Spread- .709Shape- normal
2 12 5663 0012233 57784 002234 8
How do they compare?Samples of 10 Samples of 40Center- 3.2Spread- 1.68Shape- skewed right
Center- 3.4Spread- .709Shape- normal
Boxplots
THE END