(b)

(c) Most of the names were 6 letters. There were a few names that were noticeably longer, Blackwell with 9 letters and Nightingale with 11 letters.
(d)

Most of the points were between 7 and 12, with no real peak. There are two noticeable outliers, Nightingale with 16 points and Blackwell with 20 points.
(e) Most letters: Nightingale; Most points: Blackwell, not the same person
(f) Fewest letters: Tukey with 5; fewest points: Gosset and Galton with 7 points.
(g)

The ratio values are much more evenly "spread out," ranging from 1 to 2 points/letter.
(h) The highest ratio at 2.4 belongs to Tukey. He didn’t have very many letter but some of them were pretty valuable. People like Nightingale have lots of points
but that’s not so surprising considering the number of letters.

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Activity 3-5 (cont):

(e) The graph should resemble the given histogram.  We see two clusters, one centered around 52 minutes and one around 79 minutes.

(f) The different subinterval widths change the histogram's appearance dramatically. With 5 subintervals the two clusters are not apparent, and with 20
subintervals the distribution looks very jagged. The most informative picture is probably the histogram with 10 subintervals.

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Activity 6-2 (cont.):

(f)
 

	min	Q1	median	Q3	max
PGA	1258745	1477245	1674819	2035231	6616585
LPGA	296347	364441	491200	604024	1591959
Seniors	631046	735064	969925	1130577	2515705

These five number summaries differ from those calculated by hand for 2 reasons: First, Minitab has actual dollar amounts, not rounded to the nearest thousand, and also Minitab uses a slightly different formula for calculating quartiles.

(g)

(h) Yes, the modified boxplots show the outliers and also how close the non-outliers come to them (or how far they are in the PGA case!).
(i) The boxplots reveal that the PGA golfers tend to make the most, followed in order by the Seniors and then the LPGA golfers. This difference is exemplified
by the realization that the lowest money winner among the PGA top 30 would be a high outlier among the LPGA top 30. Also, the lowest money winner among
the Seniors' top 30 is higher than the upper quartile among the women's top 30. The PGA winnings show the most variability (widest box). All three distributions of earnings are skewed to the right (lower quartile is closer to median than upper quartile).

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Activity 9-1

(a)-(c)

	strongly positive		mildly positive		virtually none		mildly negative		strongly negative
letter:	B	F	I	E	C	H	A	G	D
r	.994	.889	.51	.235	-.081	-.244	-.45	-.721	-.907

(d) largest: 1;  smallest: -1
(e) Correlations of 1 or -1 occur when the observations pairs form a straight line.
(f) A positive correlation indicates a positive association.  A negative correlation indicates a negative association
(g) Correlation values near + 1 are strong, while values near 0 are weak.
(h) There appears to be a strong association.
(i) r = .257;  This value seems to indicate a relatively weak positive relationship.  This is not consistant with our answer for (g).  This happened because r measures the strength of the linear association. While these variables are clearly related, they are not linearly related.
(j) r = .507;  This indicates a moderate positive association, though one would not guess this from the scatterplot.

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Activity 10-2: Airfares (cont.)

(a)

		mean	std. dev
airfare (y)		166.9	59.5
distance (x)		713	403

r = .795
(b) b =.795(59.5/403) = .117;  a = 166.9-.117(713) = 83.479
(c) airfare = 83.479 + .117 * distance
(d) airfare = 83.479 + .117 * distance
(e)  83.479+.117(300) = $118.58
(f) $258.98
(g)-(h)

(i)Answers will vary from student to student, but a good estimate would be $190.
(j) $188.78
(k) $415.99;  This is probably not a reliable estimate since a distance of 2,842 miles is well beyond our data set.
(l)

distance	900	901	902	903
predicted airfare	$188.78	$188.89	$189.01	$189.13

(m) Each mile adds about another $0.11, which is close to the slope of our least squares regression line, .117.
(n) $11.70

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Activity 17-1: Coin Ages (cont.)

(a)

size	mean	std. dev	min	Q1	median	Q3	max
1000	12.264	9.613	0	4	11	19	59

(b)

(c) observational units: pennies;  variable: age, quantitative
(d) parameters;  mean: m;  standard deviation: s
(e) Students' answers to (e)-(m) may differ since the data are chosen randomly.  These are meant to be sample answers.
13, 24, 17, 0, 0

(f) 10.8
(g)

Sample no.	1	2	3	4	5
Sample mean	10.8	13	5.8	12.8	17.8

(h) No, this is an example of sampling variability.  This is a quantitative variable, rather than a categorical one.
(i) mean of  values: 12.04;  standard deviation of x-bar values: 4.33
(j) This mean is reasonably close to the population mean.  This standard deviation is less than the population standard deviation.
(k)
(l) This distribution appears to centered near the population mean of 12.264.  The values are less spread out than the population distribution and the five sample means of size 5.
(m) yes

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