{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Lecture11A - 30 May 2003 Biostatistics 6650-L11A 1 Todays...

Info icon This preview shows pages 1–8. Sign up to view the full content.

View Full Document Right Arrow Icon
30 May 2003 Biostatistics 6650--L11A 1
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
30 May 2003 Biostatistics 6650--L11A 2 Today’s Schedule ANOVA general/assumptions example
Image of page 2
30 May 2003 Biostatistics 6650--L11A 3 ANOVA: general What if we want to compare means for more than 2 groups? Could use multiple 2-sample t-tests 5 groups….. 5 C 2 or 10 pairwise tests if groups have common variance, is there a more efficient method? ANOVA(analysis of variance) is the usual solution Null Hypothesis: 3 groups: H o : 0 1 =0 2 =0 3 k groups: H o : 0 1 =0 2 =…= μ k Alternative Hypothesis: – H 1 : At least one mean is different from the others
Image of page 3

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
30 May 2003 Biostatistics 6650--L11A 4 ANOVA: general ANOVA is very powerful tool. Can analyze a wide variety of study designs. Completely randomized designs effect of exercise, diet, insulin on HbA1C in DMII patients effect of fish-oil dose(none, 3, 6, 9g/day) on renal function » estimate linear dose effects Two-way ANOVA effect of treatment and sacrifice time on tumor growth in mice Factorial designs Ex: 2 3 factorial--effect of calorie restriction(none,20%), exercise(yes,no), and weight(normal, overweight) on energy expenditure; study all 8 combinations, allows us to examine main effects and interactions
Image of page 4
30 May 2003 Biostatistics 6650--L11A 5 ANOVA: general ANOVA works by partitioning the total variation in the data into pieces from various sources
Image of page 5

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
30 May 2003 Biostatistics 6650--L11A 6 ANOVA: general Notation: x ij = j th observation in the i th group Group 1 Group 2 Group 3 x 11 =3 x 21 =6 x 31 =9 x 12 =5 x 22 =1 x 32 =10 x 13 =4 x 23 =7 x 33 =7 x 24 =4 x 34 =8 n 1 =3 n 2 =4 n 3 =4 N=11 =4 =4.5 =8.5 =5.818 1. x 2. x 3. x .. x th i. 1 i 1 1 1 1 is the sample size for group i, i=1,2,...,K x = , is the mean for the i group n 1 , is the total sample size x..= , is the grand mean N i i n i ij j n K K i ij i i j n x N n x = = = = = ∑ ∑
Image of page 6
30 May 2003 Biostatistics 6650--L11A
Image of page 7

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 8
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern