Practice Questions 8.2

  1. In the ANOVA table, what is the major meaning of the result shown below?





    A.
  2. How is the value of the Actual Variance found?




    D.
  3. How is the value of the Theoretical Variance found?

    A. By using the sampling distribution of the sample average

    B. By getting the variance from the F-table and dividing by
    √n
    C. By using Levene's test to find out the value of the variances.
    D. By calculating the pooled variance
    (s²_pooled)
    A.
  4. What is the statistical importance of Pooling the variances?




    D.
  5. The ANOVA fraction gives a test statistic that follows what distribution?




    A.
  6. What does the F-distribution look like?




    C.
  7. Use the information below to find the value of the Actual Variance.
    Brand n  x̄
    A 9 5 9
    B 9 10 10
    C 9 15 11





    A.

    Find average: (5+10+15)/3= 10

    Find (x-x̄): 5-10= -5, 10-10= 0, 15-10= 5

    Find (x-x̄)²: -5²= 25, 0²= 0, 5²= 25

    • (25+0+25)/ n-1
    • = 50 / 3-1

    =25
  8. Use the information below to find the value of the Pooled variance.

    Brand n
    A 9 5 9
    B 9 10 10
    C 9 15 14





    C.

    • Pooled Variance= ((n1-1)(s²1)+(n2-1)(s²2)) / (n1 + n2 - 2)
    • = ((9-1)(9)+(9-1)(10)+(9-1)(14)) / (27-3)
    • =11

    In this case, since there is 3 brands, instead of stopping at n2, you do the same formula with n3.
  9. Use the information below to find the value of the Theoretical Variance.
    Brand n
    A 9 5 19
    B 9 10 13
    C 9 15 22

    s²_pooled= 18




    B.

    • Theoretical variance= s²_pooled / n
    • = 18 / 9
    • =2
  10. Use the information below to find the value of the ANOVA fraction.
    Brand n
    A 9 5 19
    B 9 10 13
    C 9 15 22

    s²actual= 25 s²theoretical= 6




    C.

    • ANOVA= Actual / Theoretical
    • = 25/6
    • =4.2
  11. Use the information below to find the value of the Actual Variance.

    Car n
    Chevy 16 10019
    Ford 16 110 21
    Chrysler 16 120 23





    B.

    Find average: (100+110+120)/3= 110

    Find (x-x̄): 100-110= -10, 110-110= 0, 120-110= 10

    Find (x-x̄)²: -10²= 100, 0²= 0, 10²= 100

    • (100+0+100)/ n-1
    • = 200 / 3-1

    =100
  12. Use the information below to find the value of the Pooled variance.

    Car n
    Chevy 16 10019
    Ford 16 110 21
    Chrysler 16 120 26





    A.

    • Pooled Variance= ((n1-1)(s²1)+(n2-1)(s²2)) / (n1 + n2 - 2)
    • = ((16-1)(19)+(16-1)(21)+(16-1)(26)) / (48-3)
    • = 22

    In this case, since there is 3 brands, instead of stopping at n2, you do the same formula with n3.
  13. Use the information below to find the value of the Theoretical Variance.

    Car n
    Chevy 16 100119
    Ford 16 110 121
    Chrysler 16 120 126

    s²pooled= 122




    D.

    • Theoretical variance= s²_pooled / n
    • = 122/16
    • =7.6
  14. Use the information below to find the value of the ANOVA fraction (called the F test statistic).

    Car n
    Chevy 16 100119
    Ford 16 110 121
    Chrysler 16 120 126

    s²actual= 100 s²theoretical= 40.6




    D.

    • ANOVA= Actual / Theoretical
    • = 100/40.6
    • = 2.46
  15. Use the information below to find the value of the Actual Variance for the number of calories in three types of hot dogs.

    Type n
    Beef 10 168.6 338.2
    Meat 10 165.1 445.0
    Poultry 10 107.1 203.2





    A.

    Find average: (168.6+165.1+107.1)/3= 146.9

    Find (x-x̄): 168.6-146.9= 21.7, 165.1-146.9= 18.2, 107.1-146.9= -39.8

    Find (x-x̄)²: 21.7²= 470.89, 18.2²= 331.24, -39.8²= 1,584.04

    • (470.89+331.24+(-1,584.04)/ n-1
    • = -781.91 / 3-1

    = 1,193
  16. Use the information below to find the value of the Pooled variance for the number of calories in three types of hot dogs.

    Type n
    Beef 10 168.6 338.2
    Meat 10 165.1 445.0
    Poultry 10 107.1 203.2





    D.

    • Pooled Variance= ((n1-1)(s²1)+(n2-1)(s²2)) / (n1 + n2 - 2)
    • = ((10-1)(338.2)+(10-1)(445)+(10-1)(203.2)) / (30-3)
    • = 328.8

    In this case, since there is 3 brands, instead of stopping at n2, you do the same formula with n3.
  17. Use the information below to find the value of the Theoretical Variance for the number of calories in three types of hot dogs.

    Type n
    Beef 10 168.6 338.2
    Meat 10 165.1 445.0
    Poultry 10 107.1 203.2

    s²pooled= 328.8




    B.

    • Theoretical variance= s²_pooled / n
    • = 328.8/16
    • = 32.9
  18. Use the information below to find the value of the ANOVA fraction (called the F test statistic) for the number of calories in three types of hot dogs.

    Type n
    Beef 10 168.6 338.2
    Meat 10 165.1 445.0
    Poultry 10 107.1 203.2

    s²actual= 1,193
    s²theoretical= 32.9




    B.

    • ANOVA= Actual / Theoretical
    • = 1,193/32.9
    • = 36.26
  19. Use the information below to find the value of the Actual Variance for the amount of sodium in three types of hot dogs.

    Type n
    Beef 10 433.4 7,339
    Meat 10 451.1 4,169
    Poultry 10 427.0 5,284





    B.

    Find average: (433.4+451.1+427.0)/3= 437.2

    Find (x-x̄): 433.4-437.2= -3.8, 451.1-437.2= 13.9, 427-437.1= -10.1

    Find (x-x̄)²: -3.8²= 14.4, 13.9²= 193.21, -10.1²= 102.0

    • (14.4+193.21+102)/ n-1
    • = 309.6 / 3-1

    = 155.8
  20. Use the information below to find the value of the Pooled variance for the amount of sodium in three types of hot dogs.

    Type n
    Beef 10 433.4 7,339
    Meat 10 451.1 4,169
    Poultry 10 427.0 5,284





    D.

    • Pooled Variance= ((n1-1)(s²1)+(n2-1)(s²2)) / (n1 + n2 - 2)
    • = ((10-1)(7,339)+(10-1)(4,169)+(10-1)(5,284)) / (30-3)
    • = 5,597

    In this case, since there is 3 brands, instead of stopping at n2, you do the same formula with n3.
  21. Use the information below to find the value of the Theoretical Variance for the amount of sodium in three types of hot dogs.

    Type n
    Beef 10 433.4 7,339
    Meat 10 451.1 4,169
    Poultry 10 427.0 5,284

    s²pooled= 5,597




    C.

    • Theoretical variance= s²_pooled / n
    • = 5,597/10
    • = 559.7
  22. Use the information below to find the value of the ANOVA fraction (called the F test statistic) for the amount of sodium in three types of hot dogs.

    Type n
    Beef 10 433.4 7,339
    Meat 10 451.1 4,169
    Poultry 10 427.0 5,294

    s²actual= 155.8 
    s²theoretical= 559.7




    B.

    • ANOVA= Actual / Theoretical
    • = 155.8/559.7
    • = 0.28
Author
GoBroncos
ID
364727
Card Set
Practice Questions 8.2
Description
Updated