3.4

5 34-wk period z-score = -.30, 40-wk period z-score = -.43, the 40wk period baby weighs less.

7 The 75 inch man is relatively taller.

9 Clayton, because his ERA was 2.3 standard deviations below national score while Felix’s was only 1.91 standard deviations below American score.

11 Ryan is better at the 100m backstroke, being 3.39 standard deviations below mean while he was 3.05 standard deviations below mean in 200m backstroke.

13 239

15

  1. 15 percent of males 3-5 months of age have head circumferences less than or equal to 41.0 cm and 85 percent of males 3-5 months of age have a head circumferences greater than 41.0 cm.

  2. 90 percent of 2 year old females have a waist circumference less than or equal to 52.7 cm and 10 percent of 2 year old females have a waist circumference greater than 52.7 cm.

  3. As age increases, height decreases.

22

  1. z-score = -0.94. Blackie is 0.94 standard deviations below the mean.

  2. Q1 = 9.15, Q2 = 9.95, Q3 = 11.1

  3. IQR=Q3-Q1, IQR = 11.1-9.15, IQR = 1.95.

  4. Lower fence = 6.2, upper fence = 8.2. One outlier is 5.7.

25 The cutoff point is roughly 574 minutes.

3.5

3

  1. Skewed right.

  2. 0, 1, 3, 6, 16

4

  1. Symmetric.

  2. -1, 2, 5, 8, 11

5

  1. 40

  2. 52

  3. Variable Y does because it’s skewed to the right while variable X is symmetric.

  4. Symmetric

  5. Skewed Right

6

  1. 16

  2. 22

  3. Y has more dispersion because it is further skewed to the left.

  4. Variable X has one outlier, with a value of 30.

  5. Variable Y is skewed to the left.

7

dat1 <- c(60,68,77,89,98)

boxplot(dat1)

8

dat2 <- c(110,140,157,173,205)

boxplot(dat2)

9

dat3 <- c(42,43,46,46,47,
         47,48,49,49,50,
         50,51,51,51,51,
         52,52,54,54,54,
         54,54,55,55,55,
         55,56,56,56,57,
         57,57,57,58,60,
         61,61,61,62,64,
         64,65,68,69)

  1. 42, 50.5, 54.5, 57.5, 69

boxplot(dat3)

  1. Symmetric with outlier