Hi, MHF I'm taking stats this semester, and my answer differs from my book's.

I am using software called R (The R Project for Statistical Computing)

My book uses software called Minitab (Statistical Analysis: Data Analysis and Statistics Software and Training | Minitab)

I have two sets of data, one for a group with a high dose of some medicine, and one for the control group:

High = 16.1 , 134.9 , 52.7 , 14.4 , 124.3 , 99.0 , 24.3 , 16.3 , 15.2 , 47.7 , 12.9 , 72.7 , 126.7 , 46.4 , 60.3 , 23.5 , 43.6 , 79.4 , 38.0 , 58.2 , 26.5 , 25.1

Control = 297.1 , 491.8 , 1332.9 , 1172.0 , 1482.7 , 335.4 , 528.9 , 24.1 , 545.2 , 92.9 , 337.1 , 102.3 , 255.1 , 100.5 , 159.9 , 168.0 , 95.2 , 132.5 , 442.6 , 15.8 , 175.6 , 131.1

I need to find for each group:

a) sample mean, variance, and standard deviation

b) sample upper and lower quartiles

c) sample median

d) construct a boxplot

e) 5th and 95th percentiles.

Here are my answers, green implies they agree with the book. Red implies they disagree, and the book's answer will be adjacent.

High Dose:

Sample mean:52.65

Sample variance:1490.315

Sample standard deviation:38.6046(not given in the book)

Upper Quartile:69.60(book: 74.38)

Lower Quartile:23.70(book: 21.70)

Sample median:45.00

5th percentile: .05(22+1) = 1.15 || 1st = 12.9 || 2nd = 14.4 || (12.9+14.4)/2 =13.65(book: 13.125)

95th percentile: .95(22+1) = 21.85 || 21st = 126.7 || 22nd = 134.9 || (126.7+134.9)/2 =80.8(book: 133.67)

Control:

Sample mean:382.7

Sample variance:175224.4

Sample standard deviation:418.5981(not given in book)

Upper Quartile:479.5(book: 501.1)

Lower Quartile:109.5(book: 101.9)

Sample median:215.3(book: 215.4 -- probably different rounding rules in our software)

5th percentile: .05(22+1) = 1.15 || 1st = 15.8 || 2nd = 24.1 || (15.8+24.1)/2 =19.95(book: 17.045)

95th percentile: .95(22+1) = 21.85 || 21st = 1332.9 || 22nd = 1482.7 || (1332.9+1482.7)/2 =1407.8(book: 1460.23)

Can anyone help me figure out why my answers are incorrect?

Thank you.