Page 59 - 2024-bfw-starnes-TPS7e-SE proofs.indd

46 UNIT 1 Exploring One-Variable Data

For Investigation Apply the skills from the section in a new (b) Do these data provide evidence that vitamin C helps
context or nonroutine way. teeth grow in guinea pigs similar to the ones used in
38. Population pyramids The histograms show the age this experiment? Justify your answer.
distribution of the population in Australia and Ethiopia
in a recent year from the U.S. Census Bureau’s interna- Multiple Choice Select the best answer for each question.
59
tional database. (This type of graph is referred to as a 40. Here are the amounts of money (cents) in coins carried
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population pyramid.) by 10 students in a statistics class: 50, 35, 0, 46, 86, 0,
5, 47, 23, 65. To make a stemplot of these data, you
would use stems
100
90 Australia (A) 0, 2, 3, 4, 5, 6, 8.
80 Ethiopia
70 (B) 0, 1, 2, 3, 4, 5, 6, 7, 8.
Age 60 (C) 0, 3, 5, 6, 7.
50
40
30 (D) 00, 10, 20, 30, 40, 50, 60, 70, 80, 90.
20
10 (E) None of these.
0
10 5 0 5 10 15 41. The histogram shows the heights (in inches) of 300
Percentage of population randomly selected high school students. Which of the
following is the best description of the shape of the dis-
tribution of height?
(a) The total population of Australia at this time was about
26 million. Ethiopia’s population was about 111 mil- 70
lion. Why did we use percentages rather than counts 60
on the horizontal axis?
50
(b) What important differences do you see between the
age distributions? Be specific. Frequency 40

39. Vitamin C and teeth Researchers performed an exper- 30
iment with 60 guinea pigs to investigate the effect of 20
vitamin C on tooth growth. Each animal was randomly
assigned to receive one of three dose levels of vitamin 10
C (0.5, 1, or 2 mg/day). The response variable was 0
the length of odontoblast cells (responsible for tooth 52 56 60 64 68 72 76
growth), in micrometers (µm). Here is a special type of Height (in.)
dotplot that displays the data: 60
(A) Roughly symmetric and single-peaked (unimodal)
(B) Roughly symmetric and double-peaked (bimodal)
(C) Roughly symmetric and multi-peaked (multimodal)
30
(D) Skewed to the left
Cell length (µm) 20 42. The dotplot shows the tuition (to the nearest $1000) for
(E) Skewed to the right

the 63 largest colleges and universities in North

10 Carolina in a recent year. 61

0.5 1 2
Dose (mg)

5 10 15 20 25 30 35 40 45 50 55
(a) How does this dotplot differ from the ones shown in Tuition ($1000s)
this section?

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