Module 1-Introduction to Data

Process of Statistical Investigation

Identify a question or problem Design a study and collect relevant data on the topic Describe the data Perform a statistical analysis Make inferences in context Contemplate and consider

1.10 Cheaters, scope of inference: Researchers studied the relationship between honesty, age, and self-control conducted an experiment on 160 children between the ages of 5 and 15. The researchers asked each child to toss a fair coin in private and to record the outcome (white or black) on a paper sheet, and said they would only reward children who report white. Half the students were explicitly told not to cheat and the others were not given any explicit instructions. Differences were observed in the cheating rates in the instruction and no instruction groups, as well as some differences across children's characteristics within each group. Can the results of the study can be generalized to the population? Should the findings of the study can be used to establish causal relationships. If the sample is randomly selected and representative of the entire population, then the results can be generalized to the target population. Furthermore, since this study is observational, the results cannot be used to infer causal relationships. If the sample is randomly selected and representative of the entire population, then the results can be generalized to the target population. Furthermore, since this study is experimental, the findings can be used to infer causal relationships. If the sample is randomly selected and representative of the entire population, then the results can be generalized to the target population. Furthermore, since this study is observational, the findings can be used to infer causal relationships. If the sample is randomly selected and representative of the entire population, then the results can be generalized to the target population. Furthermore, since this study is experimental, the findings cannot be used to infer causal relationships.

If the sample is randomly selected and representative of the entire population, then the results can be generalized to the target population. Furthermore, since this study is experimental, the findings can be used to infer causal relationships.

1.26 City council survey: A city council has requested a household survey be conducted in a suburban area of their city. The area is broken into many distinct and unique neighborhoods, some including large homes, some with only apartments, and others a diverse mixture of housing structures. Identify the sampling methods described below, and comment on whether or not you think they would be effective in this setting. b) Divide the city into neighborhoods, randomly sample 10 neighborhoods, and then randomly sample 20 households from those neighborhoods Simple Random Multistage Convenience Systematic Cluster Stratified

Multistage

An auto analyst is conducting a satisfaction survey, sampling from a list of 10,000 new car buyers. The list includes 2,500 Ford buyers, 2,500 GM buyers, 2,500 Honda buyers, and 2,500 Toyota buyers. The analyst selects a sample of 400 car buyers, by randomly sampling 100 buyers of each brand. Is this an example of a simple random sample? Yes, because each buyer in the sample had an equal chance of being chosen. Yes, because car buyers of every brand were equally represented in the sample. No, because every possible 400-buyer sample did not have an equal chance of being chosen. No, because the population consisted of purchasers of four different brands of car.

No, because every possible 400-buyer sample did not have an equal chance of being chosen.

An article tiled: Risks: Smokers Found More Prone to Dementia states the following:"Researchers analyzed data from 23,123 health plan members who participated in a voluntary exam and health behavior survey from 1978 to 1985, when they were 50-60 years old. 23 years later, about 25% of the group had dementia, including 1,136 with Alzheimer's disease and 416 with vascular dementia. After adjusting for other factors, the researchers concluded that pack-a-day smokers were 37% more likely than nonsmokers to develop dementia, and the risks went up with increased smoking; 44% for one to two packs a day; and twice the risk for more than two packs."Based on this study, can we conclude that smoking causes dementia later in life? Explain your reasoning. No, this is an experimental study No, this is an observational study Yes, this is an observational study Yes, this is an experimental study

No, this is an observational study

Another article titled The School Bully Is Sleepy states the following: "The University of Michigan study, collected survey data from parents on each child's sleep habits and asked both parents and teachers to assess behavioral concerns. About a third of the students studied were identified by parents or teachers as having problems with disruptive behavior or bullying. The researchers found that children who had behavioral issues and those who were identified as bullies were twice as likely to have shown symptoms of sleep disorders." A friend of yours who read the article says, "The study shows that sleep disorders lead to bullying in school children." Is this statement justified? If not, how best can you describe the conclusion that can be drawn from this study? Yes, this is an experimental study No, this is an observational study No, this is an experimental study Yes, this is an observational study

No, this is an observational study

Identify the bias: Identify the primary bias in the following scenarios. a) Students at an elementary school are given a questionnaire that they are asked to return after their parents have completed it. One of the questions asked is, "Do you find that your work schedule makes it difficult for you to spend time with your kids after school?" Of the parents who replied, 85% said "no". Based on these results, the school officials conclude that a great majority of the parents have no difficulty spending time with their kids after school. -Sampling bias. Only the students at the one elementary school were selected to fill out the questionnaire. -Response bias. Parents may feel like they will receive negative reprecussions if they answer the question honestly. -Non-response bias. The parents who returned the surveys are probably those who do not have difficulty spending time with their kids after school. Parents who work might not have returned the surveys since they probably have a busier schedule.

Non-response bias. The parents who returned the surveys are probably those who do not have difficulty spending time with their kids after school. Parents who work might not have returned the surveys since they probably have a busier schedule.

Does this describe an observational study or an experiment? The hair color of shoppers at the mall were recorded Experiment Observational Study

Observational Study

Heights of players on the New York Yankees Categorial or Quantitative?

Quantitative

In a study, the data you collect is Number of twitter followers. This data is: Quantitative or Qualitative

Quantitative

The 2006 American League Home Run totals by team Categorial or Quantitative?

Quantitative

The State Education Department requires local school districts to keep these records on all students: age, race or ethnicity, days absent, current letter grade, standardized test scores in reading and mathematics, and any disabilities or special educational needs the student may have. Which of the following are categorical (or qualitative) variables in these records? Days Absent Race or Ethnicity Disabilities or Special Needs Student Mathematics Test Score Current Letter Grade Age Reading Test Score

Race or Ethnicity Disabilities or Special Needs Current Letter Grade

Identify the bias: Identify the primary bias in the following scenarios. b) A survey is conducted on a simple random sample of 1,000 women who recently gave birth, asking them about whether or not they smoked during pregnancy. A follow-up survey asking if the children have respiratory problems is conducted 3 years later, however, only 567 of these women are reached at the same address. The researcher reports that these 567 women are representative of all mothers. -Response bias. The mothers may think they are being judged if they are asked about smoking during pregnancy. -Non-response bias. Of those 567 women asked the follow-up survey some will not return the follow-up survey. -Sampling bias. It is unlikely that the women who were reached at the same address 3 years later are a random sample. These missing responders are probably renters (as opposed to homeowners) which means if we do not include renters we then we do not have a representative sample.

-Sampling bias. It is unlikely that the women who were reached at the same address 3 years later are a random sample. These missing responders are probably renters (as opposed to homeowners) which means if we do not include renters we then we do not have a representative sample.

What is a parameter? -an unknown value from the population -a known value from an observed sample

-an unknown value from the population

asking people on the street - surveying every 3rd driver coming through a tollbooth - dividing by population by voting precinct, and sampling everyone in the precints selected - writing everyone's name on a playing card, shuffling the deck, then choosing the top 20 cards - divide the population by age and select 5 people from each age Sampling Method Stratified Convenience Cluster Systematic Simple Random

-b -d -c -e -a

Stealers, study components: In a study of the relationship between socio-economic class and unethical behavior, 129 University of California undergraduates at Berkeley were asked to identify themselves as having low or high social-class by comparing themselves to others with the most/least money (rounded to the nearest dollar), most/least education, and most/least respected jobs. They were also presented with a jar of individually wrapped candies and informed that the candies were for children in a nearby laboratory, but that they could take some if they wanted. After completing some unrelated tasks, participants reported the number of candies they had taken. It was found that those who were identified as upper-class took more candy than others (Piff, 2012). Identify the following about this study. a) What are the observational units? -the social class of the students -the 129 University of California undergraduates at Berkeley the candy in the jar -all University of California undergraduates at Berkeley

-the 129 University of California undergraduates at Berkeley

1.5 Cheaters, study components: Researchers studying the relationship between honesty, age, and self-control conducted an experiment on 160 children between the ages of 5 and 15. Participants reported their age, sex, and whether they were an only child or not. The researchers asked each child to toss a fair coin in private and to record the outcome (white or black) on a paper sheet, and said they would only reward children who report white. Half the students were explicitly told not to cheat and the others were not given any explicit instructions. In the "no instruction" group the probability of cheating was found to be uniform across groups based on a child's characteristics. In the group that was explicitly told to not cheat, girls were less likely to cheat, and while rate of cheating didn't vary by age for boys, it decreased with age for girls (Ritz et al. 2000). Identify the following What are the observational units? -the 160 children between the ages of 5 to 15 -the coin flips -all children ages 5 to 15 -boys or girls

-the 160 children between the ages of 5 to 15

A 2019 Gallup poll of randomly selected American voters reported that 16% of Republicans surveyed and 77% of Democrats surveyed consider themselves "Concerned Believers" in climate change. Which of the following is a true statement?

16% and 77% are statistics since they summarize sample data.

1.10 Cheaters, scope of inference: Researchers studied the relationship between honesty, age, and self-control conducted an experiment on 160 children between the ages of 5 and 15. The researchers asked each child to toss a fair coin in private and to record the outcome (white or black) on a paper sheet, and said they would only reward children who report white. Half the students were explicitly told not to cheat and the others were not given any explicit instructions. Differences were observed in the cheating rates in the instruction and no instruction groups, as well as some differences across children's characteristics within each group. Identify the sample for this study. 160 children between the ages of 5 and 15 The researchers 80 children between the ages of 5 and 15 who were told not to cheat All children between the ages of 5 and 15

160 children between the ages of 5 and 15

According to a Harris poll, 45% of Americans have brown eyes. Does the proportion of people with brown eyes in your class support this claim?

250 students 120 brown eyes 130 non-brown eyes What percent has brown eyes? 48% Is the value 45%? Does it seem close enough the 45% that the difference is just due to chance? Yes Does the class support the claim that 45% of Americans have brown eyes? Yes Is there anything about our study that should make us think twice about our conclusion? What could we do to answer this question better? 1. Simple sample 2. Small sample

A political scientist surveys 34 of the current 81 representatives in a state's legislature. What is the size of the sample: What is the size of the population:

34, 81

Describe the difference between a statistic and a parameter. -A parameter is computed from information gathered using a statistical sampling technique. A statistic uses information gathered using a nonstatistical sampling technique. -A statistic is a descriptive numerical measure computed from an entire population. A parameter is the corresponding measure for a sample. -A parameter is a descriptive numerical measure computed from an entire population. A statistic is the corresponding measure for a sample. -A statistic is computed from information gathered using a statistical sampling technique. A parameter uses information gathered using a nonstatistical sampling technique.

A parameter is a descriptive numerical measure computed from an entire population. A statistic is the corresponding measure for a sample.

Quantitative

A type of variable that can take on numerical values (quantities), where it is sensible to add, subtract, or take averages of those values.

1.10 Cheaters, scope of inference: Researchers studied the relationship between honesty, age, and self-control conducted an experiment on 160 children between the ages of 5 and 15. The researchers asked each child to toss a fair coin in private and to record the outcome (white or black) on a paper sheet, and said they would only reward children who report white. Half the students were explicitly told not to cheat and the others were not given any explicit instructions. Differences were observed in the cheating rates in the instruction and no instruction groups, as well as some differences across children's characteristics within each group. a) Identify the population of interest in the study. 160 children between the ages of 5 and 15 The researchers All children between the ages of 5 and 15 80 children between the ages of 5 and 15 who were told not to cheat

All children between the ages of 5 and 15

Determine whether each variable is categorical or quantitative. (i) temperature quantitative (ii) telephone area code categorical (iii) birth city categorical (iv) number of siblings quantitative

Answer 1:quantitative Answer 2:categorical Answer 3:categorical Answer 4:quantitative

Classify the variable as a categorical or quantitative -gender -temperature -nation of origin -number of siblings -number of days worked -grams of carbohydrates in a donut -phone number -zip code

C-gender-male, female, non-binary -temperature -nation of origin -number of siblings -number of days worked -grams of carbohydrates in a donut -phone number -zip code

Eye color Categorial or Quantitative?

Categorial

Movie ratings of one, two, three, or four stars Categorial or Quantitative?

Categorial

In a study, the data you collect is Favorite candy bar. This data is: Quantitative or Categorical

Categorical

In a study, the data you collect is Mood on a Happy/OK/Sad scale. This data is: Quantitative or Categorical/Qualitative

Categorical/Qualitative

Systematic Sample:

Choosing every kth individual from a random starting point. This is especially useful when you do not have a frame.

1.26 City council survey: A city council has requested a household survey be conducted in a suburban area of their city. The area is broken into many distinct and unique neighborhoods, some including large homes, some with only apartments, and others a diverse mixture of housing structures. Identify the sampling methods described below, and comment on whether or not you think they would be effective in this setting. Divide the city into neighborhoods, randomly sample 10 neighborhoods, and sample all households from those neighborhoods Multistage Systematic Simple Random Cluster Convenience Stratified

Cluster

cluster sampling

Cluster Sample: the population is divided by black lines into smaller groups (clusters), then one of these clusters is selected at random to form the sample

Is this value from a discrete or continuous data set. The average rainfall in July in inches Continuous or Discrete

Continuous

1.26 City council survey: A city council has requested a household survey be conducted in a suburban area of their city. The area is broken into many distinct and unique neighborhoods, some including large homes, some with only apartments, and others a diverse mixture of housing structures. Identify the sampling methods described below, and comment on whether or not you think they would be effective in this setting. Sample the 200 households closest to the city council offices Systematic Multistage Convenience Simple Random Stratified Cluster

Convenience

In a study, the sample is chosen by asking our 40 closest friends What is the sampling method? Simple Random Systematic Stratified Cluster Convenience

Convenience

Simple Random Sample:

Each individual has an equal chance of being selected

An orthopedist administers a questionnaire to 30 of his physically active patients who do not have any joint problems and finds that 20 of them regularly go running. He concludes that running decreases the risk of joint problems. Sampling bias. The orthopedist is only studying patients who are physically active. If you are physically active you are already less likely to have joint problems and may not represent the population of her patients. The orthopedist should instead take a random sample of all her patients and then examined whether or not the patient ran or if the patient had joint problems or not. Non-response bias. Of the 30 patients questioned some are likely not to respond to the questions. Response bias. The physically active patients want to present a good image of physical health and so are likely to lie about whether or not they have joint issues.

Sampling bias. The orthopedist is only studying patients who are physically active. If you are physically active you are already less likely to have joint problems and may not represent the population of her patients. The orthopedist should instead take a random sample of all her patients and then examined whether or not the patient ran or if the patient had joint problems or not.

1.26 City council survey: A city council has requested a household survey be conducted in a suburban area of their city. The area is broken into many distinct and unique neighborhoods, some including large homes, some with only apartments, and others a diverse mixture of housing structures. Identify the sampling methods described below, and comment on whether or not you think they would be effective in this setting. a) Randomly sample 50 households from the city Multistage Simple Random Cluster Stratified Convenience Systematic

Simple Random

1.26 City council survey: A city council has requested a household survey be conducted in a suburban area of their city. The area is broken into many distinct and unique neighborhoods, some including large homes, some with only apartments, and others a diverse mixture of housing structures. Identify the sampling methods described below, and comment on whether or not you think they would be effective in this setting. e) Walk through town and survey the 16th residence and then every 30th residence afterwards Cluster Stratified Convenience Simple Random Systematic Multistage

Simple Random

In a study, the sample is chosen by putting people's names on a dartboard, and blindly throwing darts What is the sampling method? Simple Random Systematic Stratified Cluster Convenience

Simple Random

Cluster Sample:

Split the population into heterogeneous groups, randomly select a number of those groups, and then measure all participants in the selected groups.

Multistage Sample:

Split the population into heterogeneous groups, randomly select a number of those groups, and then take a simple random sample within each selected group.

Stratified Sample:

Split up the population into homogeneous groups and then take a simple random sample within each group.

1.26 City council survey: A city council has requested a household survey be conducted in a suburban area of their city. The area is broken into many distinct and unique neighborhoods, some including large homes, some with only apartments, and others a diverse mixture of housing structures. Identify the sampling methods described below, and comment on whether or not you think they would be effective in this setting. Divide the city into 3 geographic neighborhoods that have similar personalities: Uptown (which is the largest), Midtown (which is the smallest), and Downtown (which is the second largest). Randomly select 25 households from the Uptown, 15 from Downtown, and 10 from Midtown Cluster Systematic Simple Random Multistage Stratified Convenience

Stratified

In a study, the sample is chosen by dividing the population by Gender, and choosing 30 people of each gender What is the sampling method?

Stratified

An insurance company selects 38 drivers out of the 217 drivers that they insure under 21 years of age, 57 drivers out of the 411 drivers that they insure between the ages of 21 and 50, and 22 drivers out of the 174 drivers that they insure over 50 years of age. What sampling method was used?

Stratified Sample Stratified samples select some observational units from all subgroups. Cluster samples select all observational units from some subgroups. Here, they are selecting some drivers from all the age groups, so it's stratified. A cluster sample would select just one or two of the age groups and then use all the drivers of the selected ages.

Which sampling method would work best to accomplish the goals of the study? You are studying the milk production per cow at dairy farms across the country. You think that average milk production might be influenced by the size of the farm, so you want to make sure to have equal representation from small family farms, medium-sized farms, and large commercial farms. Stratified Sampling

Stratified Sampling First separate the population of dairy farms into small family farms, medium-sized farms, and large commercial farms. Then take a sample of a particular size from each group to form your sample.

In a study, the sample is chosen by surveying every 3rd driver coming through a tollbooth What is the sampling method? Simple Random Systematic Stratified Cluster Convenience

Systematic

A dermatologist randomly assigns half of her adolescent patients to try a new medicine for acne. The other half of her patients receive the standard medicine. After two months on the medicines, the patients who tried the new medicine were more improved than the patients who received the standard medicine. This is an experiment since treatments are imposed, so causation can be concluded.

The difference between an observational study and an experiment is that in an experiment, treatments are assigned. Since the dermatologist assigned her patients the medicine, this is an experiment. Experiments allow causation.

We directly measured the height for the entire population of men at Salt Lake Community College. We found the average to be 5 feet 7 inches. We directly measured the height for a sample of 30 men at Salt Lake Community College. We found the average of these 30 heights to be 6 feet 1 inch. -The parameter is 6 feet 1 inch and the statistic is 5 feet 7 inches. -The parameter is 5 feet 7 inches and the statistic is 6 feet 1 inch. -The parameter is all male students at SLCC. The statistic is the 30 selected male students. -The parameter is the 30 selected male students. The statistic is all male students at SLCC.

The parameter is 5 feet 7 inches and the statistic is 6 feet 1 inch.

1.11 Buteyko method, scope of inference: A study investigates using the Buteyko shallow breathing technique to reduce asthma symptoms and improve quality of life. As part of this study 600 asthma patients aged 18-69 who relied on medication for asthma treatment were recruited and randomly assigned to two groups: one practiced the Buteyko method and the other did not. Those in the Buteyko group experienced, on average, a significant reduction in asthma symptoms and an improvement in quality of life. Identify the population of interest and the sample in the study. -The population is all asthma patients aged 18-69 who relied on medication for asthma treatment. The sample is the asthma patients aged 18-69 who practiced Buteyko method. -The population is the 600 asthma patients aged 18-69 who relied on medication for asthma treatment. The sample is the asthma patients aged 18-69 who practiced Buteyko method. -The population is the 600 asthma patients aged 18-69 who relied on medication for asthma treatment. The sample is all the asthma patients who relied on medication for asthma treatment. -The population is all asthma patients aged 18-69 who relied on medication for asthma treatment. The sample is the 600 asthma patients who relied on medication for asthma treatment.

The population is all asthma patients aged 18-69 who relied on medication for asthma treatment. The sample is the 600 asthma patients who relied on medication for asthma treatment.

1.5 Cheaters, study components: Researchers studying the relationship between honesty, age, and self-control conducted an experiment on 160 children between the ages of 5 and 15. Participants reported their age, sex, and whether they were an only child or not. The researchers asked each child to toss a fair coin in private and to record the outcome (white or black) on a paper sheet, and said they would only reward children who report white. Half the students were explicitly told not to cheat and the others were not given any explicit instructions. In the "no instruction" group the probability of cheating was found to be uniform across groups based on a child's characteristics. In the group that was explicitly told to not cheat, girls were less likely to cheat, and while rate of cheating didn't vary by age for boys, it decreased with age for girls (Ritz et al. 2000). Identify the following What are the variables and their types? -The variables and types are age (discrete), sex (quantitative), whether they were an only child or not (categorical), the result of the coin flip (categorical), whether the children were given instructions or not (categorical) -The variables and types are age (discrete), sex (categorical), whether they were an only child or not (categorical) -The variables and types are age (discrete), sex (categorical), whether they were an only child or not (categorical), the result of the coin flip (categorical), whether the children were given instructions or not (categorical), and whether the child cheated (categorical) -The variables and types are age (discrete), sex (quantitative), whether they were an only child or not (categorical), the result of the coin flip (categorical), whether the children were given instructions or not (categorical), and whether the child cheated (categorical)

The variables and types are age (discrete), sex (categorical), whether they were an only child or not (categorical), the result of the coin flip (categorical), whether the children were given instructions or not (categorical), and whether the child cheated (categorical)

Stealers, study components: In a study of the relationship between socio-economic class and unethical behavior, 129 University of California undergraduates at Berkeley were asked to identify themselves as having low or high social-class by comparing themselves to others with the most/least money (rounded to the nearest dollar), most/least education, and most/least respected jobs. They were also presented with a jar of individually wrapped candies and informed that the candies were for children in a nearby laboratory, but that they could take some if they wanted. After completing some unrelated tasks, participants reported the number of candies they had taken. It was found that those who were identified as upper-class took more candy than others (Piff, 2012). Identify the following about this study. What are the variables and their types? The variables and types are social class (categorical), number of candy taken (continuous), amount of money (discrete), educational level (continuous), job status (categorical) The variables and types are social class (categorical), number of candy taken (discrete), amount of money (discrete), educational level (categorical), job status (categorical) The variables and types are social class (categorical), number of candy taken (continuous), amount of money (discrete), educational level (categorical), job status (categorical) The variables and types are social class (quantitative), number of candy taken (discrete), amount of money (continuous), educational level (categorical), job status (categorical)

The variables and types are social class (categorical), number of candy taken (discrete), amount of money (discrete), educational level (categorical), job status (categorical)

A college student decides to conduct an experiment to see which dating site is best at finding him a date. He randomly selects ten individuals from three different dating sites. For the first site, he invites the individuals to meet for lunch. For the second site, he invites individuals to go dancing. For the third site, he invites individuals to see a movie. He plans to compare the number of individuals who accept his invitations for the three sites. What, if anything, is wrong with this study?

There is confounding between the dating site and the activity he invites the individuals to. Confounding happens when you can't tell where differences you see come from. For example, if the third group got the fewest acceptances, we don't know if it's because people don't like to go to movies on first dates or if people on the third dating site are less likely to accept dates from this particular person.

The Human Resources manager, in charge of hiring and firing at a large company, interviews the first 15 employees to arrive at work on a particular day and asks them whether they have ever lied on their time cards to show that they worked longer than they actually had. Which of the following statements is NOT correct?

There is non-response bias because only 15 employees were interviewed and since it's a large company, there were many employees who were not interviewed. This is a convenience sample since they used the first employees to arrive at work, rather than randomly selecting them. Non-response is when observational units in the sample do not respond, not when individuals in the population are not included in the sample.

Which of the following statements is false about the principles of a good experiment? Studying many observational units (e.g. including many patients in a study) is often more helpful than just including a few observational units in the study. Randomizing individuals into groups is one way of preventing accidental bias from creeping into a study. Using a control group with a placebo is important since otherwise subjects in the control group may behave differently than those in the treatment group. If we collect more information on each observational unit (e.g. take repeated measurements on each individual) that might be helpful to obtaining more precise results in an experiment. We can always generalize the result of a study to the greater population so long as we randomize which patients go into which study groups. Considering (controlling) more variables in planning an experiment helps ensure each study group is similar to the other study groups.

We can always generalize the result of a study to the greater population so long as we randomize which patients go into which study groups.

1.5 Cheaters, study components: Researchers studying the relationship between honesty, age, and self-control conducted an experiment on 160 children between the ages of 5 and 15. Participants reported their age, sex, and whether they were an only child or not. The researchers asked each child to toss a fair coin in private and to record the outcome (white or black) on a paper sheet, and said they would only reward children who report white. Half the students were explicitly told not to cheat and the others were not given any explicit instructions. In the "no instruction" group the probability of cheating was found to be uniform across groups based on a child's characteristics. In the group that was explicitly told to not cheat, girls were less likely to cheat, and while rate of cheating didn't vary by age for boys, it decreased with age for girls (Ritz et al. 2000). Identify the following What is the main research question? -Do girls cheat more or less often than boys? -Do children follow directions? -What is the effect of age, sex, only child status, and whether or not children were given instructions on the rate of cheating in a game?

What is the effect of age, sex, only child status, and whether or not children were given instructions on the rate of cheating in a game?

Stealers, study components: In a study of the relationship between socio-economic class and unethical behavior, 129 University of California undergraduates at Berkeley were asked to identify themselves as having low or high social-class by comparing themselves to others with the most/least money (rounded to the nearest dollar), most/least education, and most/least respected jobs. They were also presented with a jar of individually wrapped candies and informed that the candies were for children in a nearby laboratory, but that they could take some if they wanted. After completing some unrelated tasks, participants reported the number of candies they had taken. It was found that those who were identified as upper-class took more candy than others (Piff, 2012). What is the main research question? What is the effect of socio-economic status on taking candy? Do university students take free food? Do the rich eat more candy than the poor?

What is the effect of socio-economic status on taking candy?

Identify the Confounding Variable: Identify a primary confounding variable if a confounding variable exists in the scenarios. a) Researchers wanted to investigate why a city had an increase in crime. They observed that as the incidence of crime increased the number of schools in the city also increased. Is there a confounding variable in this scenario? Yes, a confounding variable could be the number of crimes in the area. Yes, a confounding variable could be the temperature. Yes, a confounding variable could be the number of schools in the area. Yes, a confounding variable could be population density in the area. No, there are no confounding variables in this situation.

Yes, a confounding variable could be population density in the area.

To determine whether increasing the amount of vegetables eaten affects body weight researchers randomly placed individuals into two groups, one where the individuals did not change anything about their lifestyle and the other group was required to eat a kale salad prepared by a certain recipe as part of their lunch every day for a month. It was determined that the individuals who ate the salad lost more weight than the those who did not change their lifestyle. Is there a confounding variable in this scenario? No, there are no confounding variables in this situation. Yes, a confounding variable could be the amount of high calorie foods eaten by the observational units. Yes, a confounding variable could be the time of the year the study was conducted. Yes, a confounding variable could be the weight of the observational units. Yes, a confounding variable could be the amount of vegetables eaten by the observational units.

Yes, a confounding variable could be the amount of high calorie foods eaten by the observational units.

Orthopedic Surgeons investigated the question, "Does running more than 25 miles in a week affect a patient's damage to the knee or knee cartilage?" The surgeons followed individuals who self-placed into two groups, those who ran more than 25 miles a week and those who did not run more than 25 miles a week. After a year, the surgeons did not find any convincing evidence of a difference of knee or cartilage damage in the two groups. Is there a confounding variable in this scenario? Yes, a confounding variable could be what type of residence the individuals live in. Yes, a confounding variable could be the time the individuals spent running per week Yes, a confounding variable could be the weight of the individuals. Yes, a confounding variable could be the knee damage or cartilage damage in the knee of the individual. No, there are no confounding variables in this situation.

Yes, a confounding variable could be the weight of the individuals.

Examine the following survey question for any sources of bias. Given that 18-year-olds are old enough to vote and to serve in the military, is it fair to set the drinking age at 21?Is the question biased? Yes, response bias No, it is not biased Yes, non-response bias Yes, sampling bias

Yes, response bias

Observation unit

a single person or object being observed

Categorical

a type of variable where responses are categories, also called a 'qualitative' variable

Data set

a way to organize data, where rows correspond to observational units and columns correspond to variables

The Human Resource department of a large company randomly selected 25 of its employees and examined their employment records to determine whether they used all their allotted sick leave the previous year. Which of the following is the population?

all employees at the company

Variables

characteristics of the observational units

The International Dairy Foods Association (IDFA) wants to study the calcium intake of male teenagers. A random sample of 50 male teenagers was observed over a period of two weeks. Researchers recorded whether they had sufficient, insufficient, or deficient calcium intake. What is the variable of interest in the study?

level of calcium intake: sufficient, insufficient, or deficient The 50 randomly selected male teenagers is the SAMPLE (the group we're collecting data from). A VARIABLE is information we observe/measure from each observational unit. So, number of milligrams of calcium consumed and whether the teenagers were male could be variables, but they are not of interest because we didn't actually measure how much calcium they consumed, but rather just whether they had enough, and we only used males so we didn't need to observe gender in the study.

1.14 Cats on YouTube: Suppose you want to estimate the percentage of videos on YouTube that are cat videos. It is impossible for you to watch all videos on YouTube so you use a random video picker to select 1000 videos for you. You find that 2% of these videos are cat videos. Determine which of the following is an observational unit, a variable, a sample statistic, or a population parameter. c) A video in your sample

observational unit

Data

observations collected from field notes, surveys, and experiments.

Determine whether the value is a parameter or statistic43.87% of voters turned out for the 2004 elections

parameter

1.14 Cats on YouTube: Suppose you want to estimate the percentage of videos on YouTube that are cat videos. It is impossible for you to watch all videos on YouTube so you use a random video picker to select 1000 videos for you. You find that 2% of these videos are cat videos. Determine which of the following is an observational unit, a variable, a sample statistic, or a population parameter. a) The percentage of all videos on YouTube that are cat videos is a/an: population parameter sample statistic variable observational unit

population parameter

Categories

possible values of a categorical variable, also called 'levels'

continuous

responses can take on infinitely many possible numerical values (must be measured, not counted)

Discrete

responses can take on only certain numerical values with spaces between numbers (usually can be counted)

1.14 Cats on YouTube: Suppose you want to estimate the percentage of videos on YouTube that are cat videos. It is impossible for you to watch all videos on YouTube so you use a random video picker to select 1000 videos for you. You find that 2% of these videos are cat videos. Determine which of the following is an observational unit, a variable, a sample statistic, or a population parameter. 2%

sample statistic

Which bias is most relevant to the following situation: A TV news program conducts a poll where viewers must pay 50 cents to call various 900 numbers to express their opinions. sampling bias nonresponse bias response bias

sampling bias

Statistic

single number summarizing a sample of data

Determine whether the value 15% is a parameter or statistic: A sample of men reveals 15% took calculus Statistic Parameter

statistic

Match the sample of students with the correct sampling method every fourth student on the class list convenience stratified random systematic cluster

systematic

What is Statistics?

the study of how best to collect, analyze, and draw conclusions from data

Statistics

the study of how best to collect, analyze, and draw conclusions from data.

1.14 Cats on YouTube: Suppose you want to estimate the percentage of videos on YouTube that are cat videos. It is impossible for you to watch all videos on YouTube so you use a random video picker to select 1000 videos for you. You find that 2% of these videos are cat videos. Determine which of the following is an observational unit, a variable, a sample statistic, or a population parameter.

variable