STATS CH 1 & 2
A study of an association between which ear is used for cell phone calls and whether the subject is left-handed or right-handed began with a survey e-mailed to 5000 people belonging to an otology online group, and 717 surveys were returned. (Otology relates to the ear and hearing.) What percentage of the 5000 surveys were returned? Does that response rate appear to be low? In general, what is a problem with a very low response rate? Of the 5000 surveys, _____ were returned. This response rate ________ to be low. What is a problem with a very low response rate?
14%; appears It creates a serious potential for getting a biased sample that consists of those with a special interest in the topic.
When a car is randomly selected, it is found to have a weight of 1852.1 kga weight of 1852.1 kg.
A continuous data set because there are infinitely many possible values and those there are infinitely many possible values and those values cannot be counted.
When a car is randomly selected, it is found to have a length of 14.71 ft
A continuous data set because there are infinitely many possible values and those those values cannot be counted
Determine whether the given value is from a discrete or continuous data set. When a car is randomly selected, it is found to have an engine with 8 cylinders
A discrete data set because there are a finite number of possible values
Determine whether the value given below is from a discrete or continuous data set. In a test of a method of gender selection comma 689 couples used the XSORT method and 547 of them had baby girls.
A discrete data set because there are a finite number of possible values
Which of the following would be classified as categorical data? Hair color Number of suitcases on a plane Amount of rainfall Tree height
Hair color
Explain the difference between a single-blind and a double-blind experiment.
In a single-blind experiment, the subject does not know which treatment is received. In a double-blind experiment, neither the subject nor the researcher in contact with the subject knows which treatment is received.
Which of the following consists of discrete data? Tree height Hair color Number of suitcases on a plane Amount of rainfall
Number of suitcases on a plane
The rankings of songs in the top 100
Ordinal
_______ are sample values that lie very far away from the majority of the other sample values.
Outliers
Determine whether the given value is a statistic or a parameter. In a study of all 4913 students at a college comma it is found that 55 % own a computer.
Parameter because the value is a numerical measurement describing a characteristic of a population.
Determine whether the data described below are qualitative or quantitative and explain why. The types of movies left parenthesis drama comma comedy comma etc. right parenthesis
Qualitative because the data don't measure or count anything.
Which of the following is NOT a level of measurement?
Quantitative
Determine whether the given value is a statistic or a parameter. Upper A sample of seniors is selected and it is found that 45 % own a television.
Statistic because the value is a numerical measurement describing a characteristic of a sample.
State whether the data described below are discrete or continuous, and explain why. The heights of different refrigerators offered by manufacturers
The data are continuous because the data can take on any value in an interval
State whether the data described below are discrete or continuous, and explain why. The heights of trees in a forest
The data are continuous because the data can take on any value in an interval
State whether the data described below are discrete or continuous, and explain why. The exact ages in hours of different cockroaches found in a certain city
The data are continuous because the data can take on any value in an interval.
State whether the data described below are discrete or continuous, and explain why. The exact weights left parenthesis in pounds right parenthesis of babies born in a certain country nothing
The data are continuous because the data can take on any value in an interval.
State whether the data described below are discrete or continuous, and explain why. The weights of dogs left parenthesis in pounds right parenthesis at a dog show
The data are continuous because the data can take on any value in an interval.
A homeowner measured the voltage supplied to his home on all 7 days of a given weekon all 7 days of a given week, and the average (mean) value is 120.6 volts.
The given value is a parameter for the week because the data collected represent a population.
Determine whether the given value is a statistic or a parameter. A homeowner measured the voltage supplied to his home on all 365 days of a given year, and the average (mean) value is 125.2 volts.
The given value is a parameter for the year because the data collected represent a population
A homeowner measured the voltage supplied to his home on one day a week for a given yearon one day a week for a given year, and the average (mean) value is 118.2
The given value is a statistic for the year because the data collected represent a sample.
Determine whether the given value is a statistic or a parameter. A homeowner measured the voltage supplied to his home on 37 random dayson 37 random days, and the average (mean) value is 127.7 volts.
The given value is a statistic for the year because the data collected represent a sample.
A homeowner measured the voltage supplied to his home on 47 random dayson 47 random days, and the average (mean) value is 107.4 volts.
The given value is a statistics for the year because the data collected represent a sample.
Determine which of the four levels of measurement (nominal, ordinal, interval, ratio) is most appropriate for the data below. Eye colors
The nominal level of measurement is most appropriate because the data cannot be ordered.
Determine which of the four levels of measurement (nominal, ordinal, interval, ratio) is most appropriate for the data below. Blood lead levels of "low comma " "medium comma " and "high"
The ordinal level of measurement is most appropriate because the data can be ordered comma but differences cannot be found or are meaningless.
Determine which of the four levels of measurement (nominal, ordinal, interval, ratio) is most appropriate for the data below. Ranks of cars evaluated by a consumer's magazine
The ordinal level of measurement is most appropriate because the data can be ordered comma but differences cannot be found or are meaningless. nothing
Determine which of the four levels of measurement (nominal, ordinal, interval, ratio) is most appropriate for the data below. Mood levels of "happy comma " "alright comma " and "sad"
The ordinal level of measurement is most appropriate because the data can be ordered comma but differences left parenthesis obtained by subtraction right parenthesis cannot be found or are meaningless. nothing
Determine whether the given value is a statistic or a parameter. A study was conducted of all 1993 workers in a certain state.A study was conducted of all 1993 workers in a certain state.
The value is a parameter because it is a numerical measurement describing some characteristic of a population.
The population of ages at inauguration of all U.S. Presidents who had professions in the military is 62, 46, 68, 64, 57. Why does it not make sense to construct a histogram for this data set?
With a data set that is so small, the true nature of the distribution cannot be seen with a histogram.
Upper class limits
are the largest numbers that can belong to the different classes
Class boundaries
are the numbers used to separate classes, but without the gaps created by class limits
Lower class limits
are the smallest numbers that can belong to the different classes
Class midpoints
are the values in the middle of the classes
To determine customer opinion of their inflight service, Continental Airlines randomly selects 120 flights during a certain week and surveys all passengers on the flights
cluster
To determine customer opinion of their musical variety, Sony randomly selects 150 concerts during a certain week and surveys all concert goers.
cluster
Currently, there is no approved vaccine for the prevention of infection by a certain virus. A clinical trial of a possible vaccine is being planned to include subjects treated with the vaccine while other subjects are given a placebo. The most appropriate is ______________________design.
completely randomized
A man experienced a tax audit. The tax department claimed that the man was audited because his name is among the first 200 names on the taxpayer list.
convenience
Determine whether the given description corresponds to an observational study or an experiment. In a study of 383 children with a particular disease, the subjects drank herbal mixtures to determine if the mixtures have an effect on the disease.
experiment
Fifty patients with brain cancer are divided into two groups. One group receives an experimental drug to fight cancer, the other a placebo. After two years, the spread of the cancer is measured. Does the description correspond to an observational study or an experiment?
experiment
A study involved 22,071 male physicians. Based on random selections, 11,037 of them were treated with aspirin and the other 11,034 were given placebos. The study was stopped early because it became clear that aspirin reduced the risk of myocardial infarctions by a substantial amount. This is an ___________ because the researchers __________________ to the individuals. What is a major problem with the study?
experimental study; apply a treatment The results apply only to male physicians.
A _______ helps us understand the nature of the distribution of a data set.
frequency distribution
Determine which of the four levels of measurement (nominal, ordinal, interval, ratio) is most appropriate. Monthly temperatures: 63 degrees Upper F comma 68 degrees Upper F comma 73 degrees Upper F comma 78 degrees Upper F comma and 83 degrees Upper F
interval
Determine which of the four levels of measurement (nominal, ordinal, interval, ratio) is most appropriate. Monthly temperatures: 65F, 69F, 73F, 77F, and 81F
interval
Monthly temperatures: 61F, 66F, 71F, 76F, and 81F
interval
Identify which of these designs is most appropriate for the given experiment: completely randomized design, randomized block design, or matched pairs design. A drug is designed to treat insomnia. In a clinical trial of the drug, amounts of sleep each night are measured before and after subjects have been treated with the drug. The most appropriate is _______________design.
matched pairs
Determine which of the four levels of measurement (nominal, ordinal, interval, ratio) is most appropriate. Hair colors
nominal
Favorite types of music
nominal
Hair Colors
nominal
Makes of computers
nominal
Types of movies (drama, comedy, adventure, documentary, etc)
nominal
Identify the level of measurement of the data, and explain what is wrong with the given calculation. In a survey, the favorite foods of respondents are identified as 0 for italian food comma 1 for mexican food comma 2 for chinese food comma and 3 for anything else. The average (mean) is calculated for 728 respondents and the result is 1.1 . The data are at the ____________ level of measurement. What is wrong withe the given calculation?
nominal Such data are not counts or measures of anything, so it makes no sense to compute their average (mean).
Research is conducted to determine if there is a relation between Parkinson's disease and childhood head trauma.
observational
Determine whether the study is an experiment or an observational study, and then identify a major problem with the study. In a survey, 1465 Internet users chose to respond to this question posted on a newspaper's electronic edition: "Is news online as satisfying as print and TV news?" 52% of the respondents said "yes." This is an _______________________ because the researchers _________________ to modify the individuals. What is a major problem with the study?
observational study; do not attempt it is a convenience sample with a voluntary response, which has a high bias of leading to bias
Positions of people in a line
ordinal
Identify the level of measurement of the data, and explain what is wrong with the given calculation. In a set of data, movie ratings are represented as 0 for 1 star comma 1 for 2 stars comma and 2 for 3 stars. The average (mean) of the 523 movie ratings is 0.9 . The data are at the ______________ level of measurement. What is wrong with the given calculation?
ordinal Such data should not be used for calculations such as an average
A parameter is a numerical measurement describing some characteristic of a ____.
population
Identify the type of observational study. Upper A researcher plans to obtain data by interviewing spouses of victims who perished in a bombing. He will interview them comma and people unrelated to the victims comma over the next 10 nbsp years to see how closeness to a traumatic event might affect recovery time.
prospective
In a poll conducted by a certain research center, 1287 adults were called after their telephone numbers were randomly generated by a computer, and 42% were able to correctly identify the vice president.
random
Ages of children: 3, 4, 5, 6, and 7
ratio
Car lengths measured in feet Length of side of a square in cm
ratio
Miles of road
ratio
Monthly Rainfall: 2.4in, 2.7in, 3in, 3.3in, and 3.6in
ratio
Voltage measurements of batteries: 1.5V, 3V, 4.5V, 6V, and 7.5V
ratio
In a _______ distribution, the frequency of a class is replaced with a proportion or percent.
relative frequency
Identify the type of observational study (cross-sectional, retrospective, or prospective) described below. A research company uses a device to record the viewing habits of about 7500 households, and the data collected over the past 5 years will be used to determinenbsp whether nbspthe proportion of households tuned to a particular sports programnbsp increased.
retrospective study
A statistic is a numerical measurement describing some characteristic of a ____.
sample
To determine her mood, Carrie divides up her day into three parts: morning, afternoon, and evening. She then measures her mood at 2 randomly selected times during each part of the day.
stratified
Upper A market researcher has partitioned all residents of a certain region into categories of unemployed comma employed full time comma and employed part time. She is surveying 47 people from each category.
stratified
A man is selected by a marketing company to participate in a paid focus group. The company says that the man was selected because every 7500 th person in the phone number listings was being selected.
stratified sampling
A researcher selects every 848th social security number and surveys the corresponding person.
systematic
A woman is selected by a marketing company to participate in a paid focus group. The company says that the woman was selected because every 2500th person in the phone number listings was being selected.
systematic
Identify the type of sampling used (random, systematic, convenience, stratified, or cluster sampling) in the situation described below. A researcher selects every 155 th social security number and surveys the corresponding person. nothing nothing nothing
systematic
To estimate the percentage of defects in a recent manufacturing batch, a quality control manager at Microsoft selects every 16th software CD that comes off the assembly line starting with the third until she obtains a sample of 140 software CDs.
systematic
Class width
the difference between consecutive lower class limits (or 2 consecutive lower class boundaries)
Determine if the following statement represents a meaningful ratio, so the ratio level of measurement applies. A movie with a 4-star rating is twice as good as one with a 2-star rating.
the ratio level of measurement does not apply
A particular country has 60 total states. If the areas of 20 states are added and the sum is divided by 20, the result is 209 comma 098 square kilometers. Determine whether this result is a statistic or a parameter.
the result is a statistic because it describes some characteristic of a sample.
Which characteristic of data is a measure of the amount that the data values vary?
variation
