intro to statistics unit 1
Select the two categories that would yield qualitative data.
a.)Age of pet b.)Color of pet c.)Pet owner's monthly income d.)Pet's purchase price e.)Type of pet Answer B & E
The amount spent on pet food each month is an example of _____ data.
a.)qualitative b.)ordinal c.)nominal d.)quantitative Answer D
Binomial Question Type
A question that will yield categorical data with just two possible values.
Confidence Interval
A range of potential values that the true value could be. It is obtained by adding and subtracting the margin of error from the value in the sample.
Percent Change
A relative increase or decrease in a percent value.
Response Variable
A variable that is affected by the explanatory variable.
Explanatory Variable
A variable that we believe is predictive of something else. An increase in this variable will correspond to an increase or decrease in some other variable.
confounding variable
A variable which was not accounted for in a study, which limits the conclusions that the study can draw.
Percentage Points
An absolute increase or decrease in a percent value.
Matched-pair design
An experimental design where two subjects who are similar with respect to variables that could affect the outcome of the experiment are paired together, then one of them is assigned to one treatment and one is assigned to the control. This can also be done by assigning each subject to both groups, where each subject acts as their own matched-pair.
non-response bias
Nonresponse bias occurs when people who are selected for the sample can't participate, either because you can't find them, or because they're actively refusing.
Confounding
Occurs when the effects of the treatments, if any, are indistinguishable from the potential effects of some other variable which was unaccounted for.
how to calculate relative change
Relative change= Absolute Change divided by original value
response bias
Response bias occurs one of two ways: either a respondent doesn't understand the question and so gives an answer that he wasn't intending; or, the respondent wants to give a supposedly correct answer to the questioner.
Select the true statement regarding the confidence interval of this scenario
The confidence interval is the range of potential values that the true value could be and is equal to 7.2 ± 0.9.
Precision
The extent to which the values are very close to each other, even if they are not near the correct value.
Accuracy
The extent to which the values, when considered all together, center around the correct value for a variable.
"handset selection" for a sample was 6.5 ± 0.3.
The mean value of the sample is the estimate, which is 6.5 and The amount by which we expect the sample value to deviate from the true value is the 0.3.
Select the statement that expresses an approach used with observational studies.
a.) "We took all those notes. We recorded customer counts, menus, food prices, even the general atmosphere of the food truck environment." b.) "We can test out locations for a brick and mortar by moving our truck. I mean, we have our social media page that gives our daily locations, but what if we found a location we like for a brick and mortar and see if our customers follow us there?" c.) "I think asking questions and collecting the information we want from our population sample is a good start." d.) "Next week, let's send out a coupon for 25% off any menu item to see if we get more customers." Answer A
Which of these situations best describes a retrospective observational study?
a.) A company using different promotions and analyzing its sales. b.) A doctor analyzing the medical history of a person. c.) A student flipping a coin and analyzing its outcomes. d.) A clinical researcher giving a medicine to a person and analyzing its effects. Answer B
Sean wants to investigate the effect of temperature on the rate of a chemical reaction. What type of variable is the temperature in Sean's experiment?
a.) Confounding b.) Dependent c.) Response d.) Explanatory Answer D because Recall that an explanatory variable is a variable that we believe is predictive of something else. Since temperature is what is affecting the rate of chemical reaction, it is the explanatory variable.
Which of these statements is NOT true regarding a randomized block design experiment?
a.) Elements are randomly selected from equal-sized blocks of the total population. b.)The elements are randomly allocated to treatment and control groups. c.)The sample is divided into participants or subjects and then grouped by a variable of interest. d.)This design has an advantage of controlling for variables that might confound the response. Answer A
Following a group of truck drivers and noting the number of miles traveled for one year refers to which type of statistical study?
a.) Experiment b.) Prospective study c.) Retrospective study d.) Case control study Answer B
Which of the following is an advantage that is unique only to experiments?
a.) Experimenters can reference sample data to draw inferences about the population. b.) Experimenters can use the data to draw cause and effect relationships. c.) Experimenters can observe and record information of interest. d.) Experimenters can work with a sample that represents the population as a whole. Answer B
Which of these represents a closed question?
a.) How will this information help you? b.) What information do you need? c.) What will this information help you do? d.) Will this information help you? Answer D
Which of these statements best explains cluster sampling?
a.) In the cluster sampling method, population is broken into groups and then elements are randomly selected in proportion from each group. b.) In the cluster sampling method, elements are randomly selected from the total population. c.) The cluster sampling method is a combination of random sampling techniques. d.) In the cluster sampling method, total population is roughly divided into groups based on location and a simple random sample of the groups is taken. Answer D
Which of these statements best defines a stratified random sample?
a.) It is a sample where every nth element of the population is selected in a sequence. b.) It is a sample where the population is first broken into homogenous groups and then elements are randomly selected, in proportion, from each group. c.) It is a sample in which every element has the same chance of being selected from the total population. d.) It is a sample where the population is divided into roughly equal groups, and then elements are randomly selected from each group. Answer B
Which of these is an example of systematic random sample?
a.) Picking out 10 names from a group of 50 students. b.) Selecting one card from a deck of 52 well-shuffled cards. c.) Choosing 10 marbles from a jar containing 40 marbles. d.) Picking out the telephone number of every 20th person from a directory. Answer D
If you were to track coffee preferences among your co-workers for the next two weeks, which type of statistical study would you be performing?
a.) Prospective study b.) Experiment c.) Case control study d.) Retrospective study Answer A
When Ben increases the temperature difference between two junctions, the voltage also increases. What type of variable is voltage in the above situation?
a.) Response b.) Independent c.) Confounding d.) Explanatory Answer A
Which of these is an example of a systematic random sample?
a.) Selecting 4 balls from a bag containing 20 balls. b.) Selecting all the students in a class of 30. c.) Picking out 10 names from a bag containing names of 50 students. d.) Selecting every 20th person in a line of 200 moviegoers Answer D
Which of these examples best represents a simple random sample?
a.) Selecting every 15th person in a group of 100 volunteers. b.) Selecting all the students in a group of 50 students. c.) Using a name generator to pick out 20 names from a group of 100 students. d.) Picking out the names of every 10th person from a group of 200 people who drive a car. Answer C
A production company is interested in collecting information on the impact of an educational documentary on everyone that watched it at the film festival.Which statement is true?
a.) The group of people that watched the documentary at the festival represents the population. b.) The production company represents the population. c.) The production company is the sample. d.) The group of people that watched the documentary at the festival is the sample. Answer A
Select the statement that expresses an approach used with experiments.
a.) The researcher should have control over all of the variables. b.) The researcher should have control over some of the variables. c.) The researcher should have control over exactly one variable. d.) The researcher should not have control over any variable. Answer B
Select the statement regarding cluster sampling that is FALSE.
a.) The total population is divided into groups. b.) Every element of some groups is included in the sample. c.) Every element of the total population has an equal probability of being selected. d.) Some of the groups are randomly selected. Answer C
Which of these represents an open question?
a.) Who helped you? b.) Can I help you? c.) How can I help you? d.) Will this help you? Answer C
A company packed 8 dark chocolates in a box of 32 assorted chocolates. Which of these does NOT represent inferential statistics?
a.)25% of the chocolates packed in a day are dark chocolates. b.)25% of the chocolates manufactured in a factory are dark chocolates. c.)25% of the chocolates manufactured in a batch are dark chocolates. d.)25% of the chocolates in a box are dark chocolates. Answer D
Which of these random samples qualifies as a representative sample if studying the opinion of the attendees to a business seminar?
a.)35 people from the company that organized the seminar b.)35 people who spoke at the seminar c.)35 people whose businesses are related to the topics discussed at the seminar d.)35 people who attended the seminar Answer D
A bakery owner asked 150 customers to taste a new type of cookie and found that 60 people liked its taste. Which of these is an example of descriptive statistics?
a.)40% of the surveyed customers like the taste of the cookie. b.)40% of all people like the taste of the cookie. c.)40% of the people in the city where the bakery is located like the taste of the cookie. d.)40% of all the bakery's customers like the taste of the cookie. Answer A
Which of these random samples qualifies as a representative sample to find out what parents think about the levels of college tuition fees in the state?
a.)50 parents of college students from the state b.)50 residents of a county in the state c.)50 residents of a city in the state d.)50 parents of college students from another state Answer A
A survey on Internet usage was conducted among a group of 200 students in the school cafeteria. It was found that 100 students spend at least two hours online every day.Which of these is an example of descriptive statistics?
a.)50% of the students in the school spend at least two hours online each day. b.)50% of the students surveyed spend at least two hours online each day. c.)50% of the students in a class spend at least two hours online each day. d.)50% of the students in the cafeteria spend at least two hours online each day. Answer B
Which of the following is NOT an example of a survey?
a.)A cell phone company randomly called 200 customers and asked about customer satisfaction. b.)Every 50th person listed in a neighborhood directory was emailed and asked about their favorite genre of music. c.)A nutritionist is studying the relationship between eating carbohydrates and gaining weight. The nutritionist recorded the diets and weights of 10 people for a year. d.)A high school student council is determining the new mascot for the school. Five students from each grade are asked what they would want as the mascot. Answer C
Which of these statements best describes a matched-pair design?
a.)A design in which the total population is randomly divided into groups of equal size and a treatment is assigned to each group. b.)A design in which an entire sample is divided into pairs, and then the pairs are matched together at random. c.)A design in which the total population is divided into homogeneous blocks and a treatment is assigned to every element of the block. d.)A design in which only two treatments are tested on pairs of similar subjects. Answer D
Which of the following is an example of a survey?
a.)A food truck owner tests out different locations for a brick and mortar by using the business's Facebook page to promote the daily location. b.)A clothing store owner asks questions to collect information from the population by taking a sample of his customers. c.)A general manager of a restaurant records customer counts and food prices to determine what changes need to be made. d.)An owner of a local pizza shop offers two new toppings to see which sells the most at the end of the day. Answer B
Which of the following is NOT an example of a survey?
a.)A human resources manager at a large company asked 50 employees in each department to rate the company on employee satisfaction. b.)A school is planning a field trip for all its students. Ten students are randomly selected from each grade and are asked where they want to go for the field trip. c.)Every 100th person listed in the telephone directory was called and asked about their all-time favorite cartoon character. d.)A researcher is trying to determine if there is a relationship between the type of plant fertilizer used and the plant height. The researcher examined records for the past three years at a nearby greenhouse. Answer D
A dealership is trying to understand its customers better. A survey was conducted among 100 customers to determine their favorite color for a sedan.Which statement is true?
a.)All people who purchased a car from the car dealer last year represent the population. b.)The 100 people surveyed represent the population. c.)All people who purchased a car from the car dealer represent the sample. d.)The 100 people surveyed represent the sample. Answer D
Which of these represents a blind experiment?
a.)Asking a group of adults to compare the taste of coffee without revealing the names of the brands. b.)Asking a group of students to choose their favorite field trip location from a list of five field trip options. c.)Asking a group of students about their favorite TV show from a list of eight TV shows. d.)Asking a group of children to choose their favorite toy from a bin containing different toys. Answer A
Which of these is an example of multi-stage sampling?
a.)Choosing New York as a sample, then selecting a sample of zip codes within New York, then sampling the names of people living in those zip codes. b.)Dividing the total population of New York into groups and then selecting people in proportion from these groups. c.)Dividing the population of New York into groups and then making simple random samples from those groups. d.)Randomly selecting elements from the entire population of New York Answer A
Which of these random samples qualifies as a representative sample if studying the opinion of people who use online shopping websites?
a.)Consumers who do not shop online b.)Consumers who order products online c.)Retailers who sell their products online d.)Employees of the online shopping websites Answer B
Which of these is an example of multi-stage sampling?
a.)Dividing the total population of Florida into groups and then selecting households in proportion from these groups. b.)Choosing Florida as a sample, then selecting a sample of school districts within Florida, then sampling the number of children in households living in those areas. c.)Dividing the population of Florida into groups and then making simple random samples of those groups. d.)Randomly selecting households from the entire population of Florida. Answer B
Which of these situations best describes randomization?
a.)Drawing a black card from a well-shuffled standard deck of 52 cards. b.)Regulating the amount of sunlight that enters a greenhouse. c.)Repeating the same cancer treatment for 100 patients to get a larger sample. d.)Changing the number of coins used in an experiment involving coin tosses. Answer A
Which of these statements about a matched-pair design is FALSE?
a.)Elements within each pair are randomly selected. b.)Possible confounding variables are controlled by matching as many characteristics as possible. c.)The matched pair must contain two distinct subjects. d.)Treatments are randomly applied to one element of each pair. Answer C
Which of these statements is true regarding a randomized block design experiment?
a.)Every nth element is selected out of the total population. b.)The probability of every element being selected from the total population is the same. c.)The total population is randomly divided into groups of equal size and a treatment is assigned to each group. d.)Random allocation of treatment and control groups is done within the divided groups. Answer D
Which of these statements best describes a randomized block design experiment?
a.)In this experiment, closely matched elements are paired, and then one of them is put in the treatment group and the other in the control group. b.)In this experiment, the subjects are divided into groups by a variable of interest and the elements are then randomly allocated to treatment and control groups within these groups. c.)In this experiment, a sample is divided roughly into some groups and then some of the groups are randomly selected. d.)In this experiment, the subjects are divided into homogeneous blocks and a treatment is assigned to every element of the block. Answer B
Which of these is true for the control group in an experiment?
a.)It is not exposed to the factor under consideration and all other external influences are held constant. b.)It is exposed to the factor under consideration and all other external influences are varied. c.)It is not exposed to the factor under consideration and all other external influences are varied. d.)It is exposed to the factor under consideration and all other external influences are held constant. Answer A
Select the FALSE statement about completely random design.
a.)It minimizes the effects of confounding variables. b.)Any number of treatments may be addressed. c.)The additional variables affect different control groups differently. d.)Subjects are randomly assigned to treatments Answer C
The American Kennel Club sponsored a national survey of 5,000 households that own pets and found that 74% of households prefer dogs.The next week, Kendra conducts an informal poll, asking every person that comes into the store if they prefer dogs to other animals. On Sunday, she enters the following information into an Excel spreadsheet: DayPercentage that Prefers Dogs Monday94% Tuesday87% Wednesday89% Thursday95% Friday91% Saturday93% Sunday89% Select the statement that is true about Kendra's measurements.
a.)Kendra's measurements are accurate but not precise. b.)Kendra's measurements are neither accurate nor precise. c.)Kendra's measurements are both accurate and precise. d.)Kendra's measurements are precise but not accurate. Answer D
Which of these data sets represent continuous data?
a.)Monthly salaries of employees b.)Number of questions answered correctly in a multiple-choice quiz c.)Heights of members of a baseball team d.)Numbers of tickets sold for a football game Answer C
Jennifer had a headache and was told she was given a name brand medicine but it was really a sugar pill. Three hours later she was asked if she feels better, and she agreed she did. What does the placebo effect mean in this specific situation?
a.)The benefit is due to the fact that Jennifer was given the treatment (pill, although only a sugar pill) and not an effect of the "active ingredient" (headache medicine). b.)The benefit is the fact that Jennifer received the treatment (pill, although only a sugar pill) and it contains another active ingredient. c.)The benefit is that Jennifer was given the control (pill, although only a sugar pill) and not the active ingredient (cough medicine). d.)Jennifer received the benefit from the treatment since she also took a nap. Answer A
Select the TRUE statement for completely random design.
a.)The experimental units are assigned randomly to exactly one control group and one or more treatment groups. b.)The experimental units are assigned randomly to one or more control groups and exactly one treatment group. c.)The experimental units are assigned randomly to exactly one control group and one treatment group. d.)The experimental units are assigned randomly to one or more control groups and one or more treatment groups. Answer A
Which of these statements is true for a matched-pair design?
a.)The matched elements within each pair are randomly assigned to different treatments. b.)The matched elements within each pair are assigned to the same treatment. c.)The matched elements within different pairs are randomly assigned to the same treatment. d.)The matched elements within different pairs are randomly assigned to different treatments. Answer A
Which of these approaches is generally done in a multi-stage sample?
a.)The population is subdivided into smaller and smaller clusters which are then sampled. b.)A sample is made by randomly picking every nth element of the total population. c.)The total population is divided into groups and then some groups are randomly selected. d.)A sample is made by randomly picking out elements from the total population. Answer A
A researcher is interested in researching weekly earnings in large cities across the country. A survey was conducted among 100 residents in a city to determine their weekly earnings. Which statement is true?
a.)The surveyed residents are the population. b.)The surveyed residents are the sample. c.)The residents in the city are the population. d.)The residents in the city are the sample. Answer B
Select the FALSE statement about completely random design.
a.)The test subjects are first broken into groups based on a certain variable of interest before being assigned to each treatment condition. b.)The test subjects are assigned to treatment levels of the primary factor at random. c.)This design can lead to disproportionate results. d.)This design is the easiest way of assigning individuals to a treatment group. Answer A
Which of these data sets represent discrete data?
a.)Time spent in running 1 mile b.)Snowfall that fell last night in Maine c.)Number of questions answered incorrectly in a multiple-choice quiz d.)Temperature readings for Tuesday afternoon Answer C
Analyzing the results of rolling a fair die 100 times refers to which of these principles?
a.)Treatment b.)Randomization c.)Replication d.)Control Answer C
Select the two categories that would yield quantitative data.
a.)Type of pet b.)Gender of pet c.)Age of pet d.)Color of pet e.)Weight of pet Answer C & E
Which of these data sets does NOT represent continuous data?
a.)Weights of potatoes in a sack b.)Gender of students in a college c.)Heights of trees at a nursery d.)Rainfall readings during a week Answer B
If numbers collected from a survey are measurements, what are these measurements called before you perform any calculations?
a.)available data b.)raw data c.)biased data d.)peer-reviewed data Answer B
If you are using new information in a survey that was not collected during previous surveys, you will be using _______ to gauge customer satisfaction.
a.)peer-reviewed data b.)biased data c.)raw data d.)available data Answer C
You find some public records about customer satisfaction in the company's archive.What type of data is this called?
a.)raw data b.)biased data c.)peer-reviewed data d.)available data Answer D
Random errors
are exactly that: random. They can simply occur through no fault of the person taking the sample. When a sample is taken from a larger population, the results are unknown, meaning that it's unclear if the results will accurately represent exactly what the population looks like. easier to avoid if using a larger sample size.
systematic errors
are mistakes. Systematic errors are due to flaws in the design. this can occur when a selection bias is present and when there is a measurement bias.
closed question
have short, definite, usually multiple choice type answers.
how to find index number
index number= new value divided by reference value x 100
Selection bias
is also called undercoverage bias. It occurs when a significant subset of the population is left out of the sample. This is not necessarily intentional, but rather, occurs when they were systematically ignored by whoever was taking the sample
Blinding
is one of those principles of experimental design whereby the subjects don't know what treatments they're going to receive.
Absolute change
is the actual change in units. It could be the actual change in pounds, degrees, inches, percentage points, or lots of different things.
Relative change
is the percent difference from the previous value, and it's always expressed as a percent.
convenience sample
that is easily obtained is not valid because people in similar locations often feel the same way.
self-selected samples
which are also called voluntary response samples. These are samples where people can choose to participate.
