Stats Chapter 1 Homework

For the following description of​ data, identify the​ W's, specify for each variable whether its use indicates that it should be treated as categorical or​ quantitative, and, for any quantitative​ variable, identify the units in which it was measured​ (or note that they were not​ provided). Because of the difficulty of weighing a crocodile in the swamp​, researchers caught and measured 83 crocodiles​, recording their​ weight, jaw length​, body​ length, and sex. They hoped to find a way to estimate weight from the​ other, more easily determined quantities.

1. 83 crocodiles 2. Weight, jaw length​, body​ length, and sex 3. This information is not given. 4. This information is not given. 5. To find an easier way to estimate the weight of a crocodile 6. Researchers collected data on the 83 crocodiles they were able to catch.

A look at 489 participants in a study found that participants who drank three or more coffees a week experienced waist size increases five times greater than those of people who​ didn't drink the coffees.

1. Identify the Who for this study - all 489 participants in the study. 2. Identify the What for this study - Number of coffees consumed per week and waist size change. 3. Identify the Population of interest - all people

Identify the​ W's, name the​ variables, specify for each variable whether its use indicates that it should be treated as categorical or​ quantitative, and, for any quantitative​ variable, identify the units in which it was measured. Scientists at a major pharmaceutical firm conducted an experiment to study the effectiveness of an herbal compound to treat the common cold. They exposed each patient to a cold​ virus, then gave them either the herbal compound or a sugar solution known to have no effect on colds. Several days later they assessed each​ patient's condition, using a cold severity scale ranging from 0 to 5. They found no evidence of benefits of the compound.

1. Identify the Who in this situation - the patients 2. Identify the What in this situation - cold severity and treatment 3. Identify the When in this situation - the When is not specified. 4. Identify the Where in this situation - the Where is not specified. 5. Identify the Why in this situation - to test the effectiveness of herbal remedy on the common cold 6. Identify the How in this situation - the scientists set up an experiment One variable, treatment, is categorical and has no units. Another variable, cold severity, ​quantitative, its units are a scale from 0 to 5.

Identify Who and What were investigated and the Population of interest. A study found that during ovulation​, a woman can tell whether a man is employed or unemployed by looking at his face. The study involved 40 undergraduate womennothingnothingnothingnothingnothing who were asked to guess the employment status of 80 men based on photos of their face. Half of the men were employed​, and the other half were unemployed. All held similar expressions in the photos. None of the women were using any contraceptive drugs at the time of the test. The result was that the closer a woman was to her peak ovulation​, the more accurate her guess.

1. The 40 undergraduate women 2. The ability to differentiate employed men from unemployed men 3. All women

A study found that after a meal​, a woman can tell whether a man is fertile or sterile by looking at his face. The study involved 40 undergraduate womennothingnothingnothingnothingnothing who were asked to guess the likely fertility of 80 men based on photos of their face. Half of the men were fertile​, and the other half were sterile. All held similar expressions in the photos. All of the women had eaten the same meal at the time of the test. The result was that the closer a woman was to her last meal​, the more accurate her guess.

1. The 40 undergraduate women. 2. The ability to differentiate fertile men from sterile men. 3. All women.

A​ person's grade in school is generally identified by a number. ​a) Give an example of a why in which grade level is treated as categorical.

A principal wants to know how many from each grade will be attending a performance of a school play.

A​ person's grade in school is generally identified by a number. ​b) Give an example of a why in which grade level is treated as quantitative.

A principal wants to see the trend in the amount of mathematics learned as students leave each grade.

A recent newspaper article reported on​ Americans' eating habits. The article reported that only about one third of American adults ate 2 or more servings of fruit per​ day, and only​ 26% ate 3 or more servings of vegetables per day. Californians ate the most​ fruit, while Tennesseans ate the most vegetables. Which of the following is NOT a variable reported in this​ study?

A. American adults

A coffee shop next to a university surveys potential​ customers: students selected randomly walking onto campus. The survey asked students where they​ live, whether they study at the​ library, and their weekly food budget.

A​ student's weekly food budget is a quantitative variable.

A recent newspaper article reported on​ American's eating habits. The article reported that only about one third of American adults ate 2 or more servings of fruit per​ day, and only​ 26% ate 3 or more servings of vegetables per day. Californians ate the most​ fruit, while Tennesseans ate the most vegetables. The phrase​ "26% ate 3 or more servings of vegetables per​ day" refers to what kind of variable and​ why?

B. The variable could be either quantitative or categorical depending on whether the subjects were asked how many servings of vegetables per day or whether they were asked if they ate 3 or more servings of vegetables per​ day, respectively.

The coffee shop next to a university surveys potential​ customers, students selected randomly walking onto campus. The survey asked students where they​ live, whether they study at the​ library, and their weekly food budget. Which of the following was NOT one of the​ "Whats"?

C. The coffee shop.

A certain poll question​ asked, "In politics comma as of today comma do you consider yourself conservative comma moderate comma or liberal question mark " The possible responses were "Conservative" comma "Moderate" comma "Liberal" comma "Other" comma and "No Response". What kind of variable is the​ response?

Categorical Variable

A certain poll question​ asked, "In the past 5 years comma do you think that things have gotten better comma stayed the same comma or gotten worse question mark " The possible responses were "Better" comma "No change" comma "Worse" comma "Don't Know" comma and "No Response". What kind of variable is the​ response?

Categorical variable

Scientists at a major pharmaceutical firm conducted an experiment to study the effectiveness of an herbal compound to treat the common cold. They exposed each patient to a cold​ virus, then gave them either the herbal compound or a sugar solution known to have no effect on colds. Several days later they assessed each​ patient's condition, using a cold severity scale ranging from 0 to 5. They found no evidence of benefits of the compound.

Identify the Who in this situation - the patients Identify the What in this situation - treatment and cold severity Identify the When in this situation - the When is not specified Identify the Where in this situation - the Where is not specified Identify the Why in this situation - to test the effectiveness of herbal remedy on the common cold Identify the How in this situation - the scientists set up an experiment One​ variable, treatment, is categorical and has no units. Another​ variable, cold severity, is quantitative and its units are a scale from 0 to 5.

A pharmaceutical company conducts an experiment in which a subject takes 100 mg of a substance orally. The researchers measure how many minutes it takes for one quarter of the substance to exit the bloodstream. What kind of variable is the company​ studying?

Quantitative Variable

A pharmaceutical company conducts an experiment in which a subject takes 200 mg of a substance orally. The researchers measure how many seconds it takes for half of the substance to exit the bloodstream. What kind of variable is the company​ studying?

Quantitative variable

The toy​ hoop, a popular​ children's toy in the​ 1950s, has gained popularity as an exercise in recent years. But does it​ work? To answer the​ question, an exercise council conducted a study to evaluate the cardio and​ calorie-burning benefits of using this​ children's toy. Researchers recorded heart rate and oxygen consumption of adult​ participants, as well as their individual ratings of perceived​ exertion, at regular intervals during a​ 30-minute workout. Identify Who and What were investigated and the Population of interest.

The Who is the participants in the study and the What is the recorded heart​ rate, oxygen​ consumption, and perceived exertion. The population of interest is all adults.

A recent newspaper article reported on​ Americans' eating habits. The article reported that only about one third of American adults ate 2 or more servings of fruit per​ day, and only​ 26% ate 3 or more servings of vegetables per day. Californians ate the most​ fruit, while Tennesseans ate the most vegetables.

The cases in this study were individual Americans.

Sports announcers love to quote statistics. During football championship​ games, they particularly love to announce when a record has been broken. They might have a list of all football championship​ games, along with the scores of each​ team, total scores for the two​ teams, margin of​ victory, passing yards for the​ quarterbacks, and many more bits of information. Identify the who in this list.

The individual games

A recent newspaper article reported on​ Americans' eating habits. The article reported that only about one third of American adults ate 2 or more servings of fruit per​ day, and only​ 26% ate 3 or more servings of vegetables per day. Californians ate the most​ fruit, while Tennesseans ate the most vegetables.

The state that a respondent lived in is a categorical variable.

A recent newspaper article reported on​ American's eating habits. The article reported that only about one third of American adults ate 2 or more servings of fruit per​ day, and only​ 26% ate 3 or more servings of vegetables per day. Californians ate the most​ fruit, while Tennesseans ate the most vegetables.

The variable could be either quantitative or categorical depending on whether the subjects were asked how many servings of vegetables per day or whether they were asked if they ate 3 or more servings of vegetables per​ day, respectively.

A coffee shop next to a university surveys potential​ customers: students selected randomly walking onto campus. The survey asked students where they​ live, whether they study at the​ library, and their weekly food budget.

The​ "Who" in this study is the students at university.