2.1

7

  1. China

  2. 50 million

  3. about 350 million

  4. This chart may be misleading because it graphs frequency instead of the relative frequency. The amounts presented in the graph are not divided by population number. Different countries have different population sizes and those countries with larger populations may be made to look as though they have more internet users. Dividing by the population to see the percent of each country that uses internet would be a more accurate representation when comparing countries to one anoher.

9

  1. 69%

  2. about 55,200,000

  3. Inferential, because the statement makes a generalization about the population of adult Americans based on the result of a sample. The statistic that 8% of the adults who were questioned believe divorce is acceptable in certain situations is being extended to the population.

11

  1. Proportion of 18-34 year-olds more likely = 0.43; Proportion of 35-44 year-olds more likely = 0.61

  2. age group 55+ years old

  3. age group 18-34 years old

  4. directly proportionate; as age increases, likelihood to buy when made in America increases. Those who are younger are less likely to buy products made in America. Those who are older are more likely to buy when made in America.

13

Never: 0.0262

Rarely: 0.0678

Sometimes: 0.1156

Most of the time: 0.2632

Always: 0.5272

  1. 52.72%

  2. 9.4%

d e f

my_data <- c(125, 324, 552, 1257, 2518)

groups <- c("Never", "Rarely", "Sometimes", "Most", "Always")

barplot(my_data, main = "Wearing Seatbelts", names.arg = groups)

barplot(my_data, main = "Wearing Seatbelts", names.arg = groups, col = c("red","blue","green","yellow", "black"))

rel_freq <- my_data / sum(my_data)

barplot(rel_freq, main = "Wearing Seatbelts", names.arg = groups, col = c("red","blue","green","yellow","black"))

pie(my_data, labels = groups, main = "Wearing Seatbelts")

  1. Inferential because it gerenalizes about the population of all college students based on the results from the sample.

15

More then 1 hour: 0.3678

Up to 1 hour: 0.1873

A few time a week: 0.1288

A few times a month: 0.079

Never: 0.2371

  1. 23.7%

c d e

my_data <- c(377, 192, 132, 81, 243)

groups <- c("More 1", "Up to 1", "Few times week", "Few times month", "Never")

barplot(my_data, main = "Use the internet", names.arg = groups)

barplot(my_data, main = "Use the internet", names.arg = groups, col = c("red","blue","green","yellow", "black"))

rel_freq <- my_data / sum(my_data)

barplot(rel_freq, main = "Use the internet", names.arg = groups, col = c("red","blue","green","yellow","black"))

pie(my_data, labels = groups, main = "Use the internet")

  1. This statement makes a generalization about the whole population of American adults based on the statistic from a sample of 1025 American adults. The problem with this statement is that it is inferential and does not have a level of confidence. Thus, it may not be truly representative of the American adult population’s internet usage.

2.2

9

  1. 8

  2. 2

  3. 15

  4. 4

  5. 15%

  6. bell-shaped

10

  1. 4

  2. 9

  3. 17%

  4. bell-shaped

11

  1. 200

  2. 10

  3. (60-69, 2) (70-79, 3) (80-89, 13) (90-99, 42) (100-109, 58) (110-119, 40) (120-129, 31) (130-139, 8) (140-149, 2) (150-159, 1)

  4. 100-109

  5. 150-159

  6. 5.5%

  7. no

12

  1. 200

  2. Skip this problem

  3. 0-199

  4. skewed right

  5. The problem with the statement is that it attributes the cause of alcohol-related deaths to the safety of the roads. It can not be assumed that the greater amount of deaths in Texas are due to Texas having worse roads than Vermont. There may be some confounding present here. A better way to compare the states would be to look for other explanatory variables, such as law enforcement or use of alcohol in the respective states.

13

  1. skewed right; the amount of lower-income and middle-income would be much higher than the amount of high-income because the population of rich, high-income people is small. Not many people make incomes in the millions

  2. bell-shaped; few people score very high or perfectly on the SAT, while few people score a 0 or very low; most of the population would score in the middle

  3. skewed right; it is not usual for family sizes to exceed more tan about 5 or 6 people; most parents dont have more than 3 kids. So, there is likely to be fewer large families and more small families.

  4. skewed left; alzheimer’s disease usually only affects the very old-aged. Thus, more elderly and very few young people are likely to have alzheimer’s

14

  1. Skewed right; more people (elderly and people below 21 years old) are likely to consume few to almost no drinks, while less people are likely to consume very many.

  2. skewed right; students in the public school district tend to be young children to adolescents; most students graduate at age 18. older ages are less likely to be students.

  3. skewed left; as people age, their hearing descreases. people who are older are more likely to be hearing-aid patients, with very few young people being likely to have hearing issues.

  4. bell-shaped; few men are likely to be very tall or very short, the average will fall in the middle with few outliers