Chapter 5 - Producing Data

Front 1

Random Digits

Back 1

A series of numbers which have no distinguishable pattern

Hint 1

Table B

19223 95024 05756 28713 96409 12531 42544 82853

Front 2

Matched Pair Design

Back 2

A way a sampling two treatments where one set of the subjects are given one treatment and the other half receive the other treatment.

Hint 2

A drug is being tested and the subjects are split into two sub-sets. One of these sub-sets is administered the drug and the other can be given a placebo or another treatment.

Front 3

Experiment

Back 3

The tester deliberately imposes their chosen treatment to force an outcome and study the response.

There is a explanatory and response variable.

Hint 3

An educator wants to compare the effectiveness of computer software that teaches reading with that of a standard reading curriculum. He tests the reading ability of each student in a class of fourth graders then divides them into two groups. One group uses a computer regularly, the other is taught with a standard curriculum. At the end, both groups are retested to see if there is an increase in reading ability.

This is an experiment, because a treatment is imposed. The explanatory variable is the teaching methods, using a computer or the standardized curriculum.
The response variable is scores in reading.

Front 4

Undercoverage

Back 4

Undercoverage occurs when some groups in the population are left out of the process of choosing a sample.

Hint 4

A shampoo manufacturer wants to test how if his shampoo encourages hair growth. He tests this by measuring the amount of hair 50 Asian women have, then having the 50 women wash their hair daily with the shampoo and measuring how much hair they have by the end of the program.

There is undercoverage in this experiment, because no other ethnicities besides Asian are tested. Some hair types may differ than Asians.

Front 5

Randomization

Back 5

the random, impersonal division of experimental units into groups or treatments in an experiment by using chance methods (random number tables, flipping a coin, etc.).

Hint 5

Front 6

Placebo Effect

Back 6

A neutral treatment that has no "real" effect on the dependent variable, which may sometimes give a favorable response.

Hint 6

"Gastric freezing" is a clever treatment for ulcers in the upper intestine. the idea is that cooling the stomach will reduce its production of acid and so relieve ulcers. thus, the design was:

Gastric freezing-->Observe pain relief

a later experiment divided ulcer patients into 2 groups. one group was treated by gastric freezing as before. the other group received a placebo treatment in which the liquid in the balloon was at body temperature rather than freezing. 34% of the 82 patients in the treatment group improved, but so did 38% of the 78 patients in the placebo group. this and other properly designed experiments showed that gastric freezing was no better than a placebo.

Front 7

Convenience sampling

Back 7

choosing individuals who are easiest to reach as a sample for a study or experiment.

Hint 7

manufacturers and advertising agencies often use interviews at shopping malls to gather info about the habits of consumers and the effectiveness of ads. a sample of mall shoppers is fast and cheap. but people contacted at shopping malls are not representative of the entire U.S. population. they are richer, for example, and more likely to be teenagers or retired. moreover, mall interviewers tend to select neat, safe-looking individuals from the stream of customers. decisions based on mall interviews may not reflect the preferences of all consumers.

Front 8

Voluntary response sample

Back 8

A biased sample that consists of people who choose themselves by responding to the general appeal.

Hint 8

The ABC network program asks a question on domestic policy and conducts call-in polls of public opinion. Any individual who wishes to give their opinion is welcome to call and answer the question.

Front 9

Experimental units

Back 9

individuals on which the experiment is done

Hint 9

plants are used as experimental units in order to test out the effectiveness of a type of fertilizer.

Front 10

subjects

Back 10

human experimental units on which the experiment is tested

Hint 10

patients in a hospital receive a certain treatment in order to test out its effectiveness.

Front 11

treatment

Back 11

a specific experimental condition applied to the experimental units.

Hint 11

A researcher uses two types of treatments for weight loss (pills and an exercise regime) on two different groups of people in order to find out which works more effectively.

Front 12

Lack Of Realism

Back 12

Subjects, treatments, or setting of an experiment may not realistically duplicate the conditions we really want to study which prevents us from using the experiment to generalize results

Hint 12

A study compares two television advertisements by showing TV programs to student subjects. The students know it's "just an experiment." The results wouldn't apply to everyday viewers and this study doesn't provide a realistic setting as the subjects know they are being tested.

Front 13

Stratified Random Sample

Back 13

Sampling method for a population

Hint 13

Divide population into groups of individuals (strata) that are similar in some way and then choose a separate SRS in each stratum and combine these SRS's to form a full sample.

Front 14

Probability Sample

Back 14

A probability sample is a sample chosen by chance. One must know what samples are possible and what chance, or probability, each possible sample has.

Hint 14

For example, a simple random sample is a probability sampling method because it gives each member of the population an equal chance to be selected.

Front 15

Double Blind

Back 15

Neither the subjects nor those who measure the response variable know which treatment a subject received.

Hint 15

For example if a doctor is giving patients either a placebo or a real treatment but neither the doctor nor the patient know whether they have the placebo or the real treatment, it is a double blind experiment.

Front 16

Observational Study

Back 16

The tester observes individuals and measures the variable of interest, but no treatment is imposed. (Observational studies do not imply a cause and effect relationship)

Hint 16

For example you are interested in whether karaoke singers who are more animated receive more applause from the audience. You visit a restaurant that has karaoke and observe karaoke singers during one evening. You rate each karaoke singer with respect to how animated the singer was. Then, you rate the degree of applause that each singer received. You then determine if there was a correlation between how animated the singers were and the applause that they received from the audience.

Front 17

Cluster Sampling

Back 17

The population is divided into groups. Randomly select a number of these clusters. All individuals in each cluster will be part of your population.

Hint 17

For example you want to know what Leland students favorite subject is. You randomly select five classes and ask all students in each class which subject they prefer.

Front 18

Sampling

Back 18

Involves studying a part in order to gain information about the whole.

Hint 18

It is a method for collecting data. For example, if you wanted to know what a class' favorite color is, you would take a sampling by asking a small group of the total population.

Front 19

Nonresponse

Back 19

Occurs when an individual chosen for the sample can't be contacted or does not cooperate

Hint 19

For example; a single individual in the sample that you conduct about kittens refuses to cooperate because he absolutely hates kittens with a fiery passion.

Front 20

Replication

Back 20

The practice of assigning each treatment to many experimental subjects. In other words, the more subjects in each treatment condition, the lower the variability of the dependent measures.

Hint 20

6 students are assigned to 3 treatment groups to discover the better studying method. Replication would be assigning 90 students to 3 treatment groups, instead.

Front 21

Comparison

Back 21

The simplest form for the "control" principle of statistical design.

Hint 21

Experiments should compare two or more treatments in order to prevent confounding the effect of a treatment with other influences, such as lurking variables.

Front 22

Census

Back 22

Attempts to contact every individual in a population.

Hint 22

A census would be if you asked all the employees who work for a company if they liked working there or not.

Front 23

Block Design

Back 23

A design in which the subjects are matched according to a variable which the experimenter controls. The subjects are put into groups (blocks) of the same size as the number of treatments. The members of each block are then randomly assigned to different treatment groups

Hint 23

A researcher is carrying out a study of the effectiveness of four different skin creams for the treatment of a certain skin disease. He has 80 subjects and plans to divide them into 4 treatment groups of 20 subjects each. Using a randomized blocks design, the subjects are assessed and put in blocks of 4 according to how severe their skin condition is; the 4 most severe cases are the first block, the next 4 most severe cases are the 2nd block, and so on to the 20th block. The 4 members of each block are then randomly assigned, one to each of the 4 treatment groups.

Front 24

Response Bias

Back 24

A biased answer to a question due to the behavior of the respondent/interviewer or the wording of the question.

Hint 24

Biased question: Even though McDonalds is very unhealthy, would you rather eat at McDonalds or Subway?
Unbiased question: Would you rather eat at McDonalds or Subway:?

Front 25

Simple Random Sample

Back 25

The basic probability sample that gives every possible sample of a given size the same chance to be chosen.

Hint 25

A group of 5 students are chosen out of a hat from a class of 30 students. In this case, the population is all 30 students, and the sample is random because each student has an equal chance of being chosen.

Front 26

Population

Back 26

To gather information from an entire group of individuals needed for the question.

Hint 26

A population of group would be if we wanted to know the grades of Leland High Schools math students so we would take all the individuals needed in order to get the information we want.

Front 27

statistical Significance

Back 27

An observational effect that is so big that it would rarely happen.

Hint 27

95% of America watching the superbowl.

Front 28

Bias

Back 28

When the sampling method systematically favors certain outcomes.

Hint 28

Convenience Sampling: choosing individuals who are easiest to reach.
Voluntary Response Sample: people who chose themselves by responding to a general appeal.

Front 29

Principles of Experimental Design

Back 29

1) Control effects of lurking variables on response, buy comparing two or more treatments.
2) Replicate each treatment on many units to reduce chance of variation in results.
3)Randomize--use impersonal chance to assign experimental units to treatments.

Hint 29

Control: use a placebo and a treated group.
Replicate: do multiple trials to get better results.
Randomize: Use numbers in a hat, your calculator, or use table B.