chapter 1
Because inferential statistics allows you to study 'samples' and then make generalizations about the 'populations', sampling error needs to be adressed to make these generalizations as accurate as possible.
'samples' 'populations'
in each of the following situations, data are obtained by conducting a research study. classify each research study as experimental or correlational. A: a research center is considering changing the incentive structure for its children with OCD,etc. B: a statistic student interested in gender and grooming collects data on the shower length,etc. C: a professor interested in exercise and overall health collects a questionnaire data from a sample of college students, etc.
A: Experimental B: Correlational C: correlational
to accomplish the goal, an experiment must do which of the following?
Manipulate an independent variable. control extraneous variables.
Judge and cable (2010) found that thinner woman had higher incomes than heavier woman. Is this an example of an experimental study or nonexperimental study?
This is not an experiment because no independent variable is manipulated. the researchers are comparing two preexisting groups of individuals.
A parameter is which of the following?
a characteristic of a population. not a independent variable or dep. variable of charac. of a sample
for the following scores find the value of each expression: X _______ -4 -2 0 -1 -1
ΣX: -8 ΣX^2: 14 Σ(x+3): 7
select the measurement scale in the right column that best matches the description in the left column, not that each scake will be used exactly once. A: The values of data measured on this scale cannot be rank ordered. B: the values of data measured on this scale can be rank ordered and have meaningful differences between scale points: C: the values of data measured on this scale can be rank ordered: D: the vales of data measured on this scales can be rank oredered and have meaningful differenec between scale points. for this scale, there is also an absolute zero point:
A: Nominal B: Interval C: Ordinal D: Ratio
use summation notation to express each of the following calculations: A: add one point to each score, then add the resulting values B: Add one point to each score and square the results. Then add the squared values. C: Add the scores and square the sum. Then subtract three points from the squared value.
A: Σ(X+1) B: Σ(X+1) ^2 C: (ΣX)^2 -3
Shaywitz, shaywitz, blachman and colleagues (2004) conducted an experiment to see whether a reading intervention base on phonetics could alter the functioning of the left hemisphere region of the brain to help children with reading disabilities read better. Some children (n=37) were randomly assigned to receive the phonologically based reading intervention, whereas another group (n=12) received the treatment that was typically used in their community. Children taught with the phonologically based reading intervention demonstrated increased activity in the left hemisphere regions of the brain during functional magnetic resonance imaging (mri) compared with those who received the typical treatment. in the experiment, the dependent variable is______, and the independent variable is _____.
Funtioning of the left hemisphere region of the brain type of reading intervention
a researcher would like to find out more about the determinants of college achievement. He conducts a study on 437 college students in which he measures their IQ levels and their grades in college courses. The researcher created five different groups using the students IQ levels and then comopared the average grades among members in different groups. the study is an example of _____ study. the grades of the college studets is the _____variable. IQ group assignments is the _____ variable
NON experimental Dependent quasi-independent
shyness if a hypothetical construct because it is ? shyness might be measured and desribed using an operational definition because?
an internal attribute or characteristic that cannot be observed directly. operational definitions provide indirect methods for examining constructs, which cannot be directly observed or measured.
Weinstein, Mcdermott, and Roediger (2010) conducted an experiment to evaluate the effectiveness of different study strategies. One part of the study asked students to prepare by reading a passage. etc. Identify the dependent variable for this study? Is the dependent variable discrete or continous? what scale of measurement is used to measure the dependent variable?
dependent variable: number of correct answers. Discrete. ratio.
suppose a researcher compiled a data set of consisting of the following variables for a sample of 200 women, for each variable, select whether it is discrete of continuous. the number of sons or daughters: the number of meals eaten out in the last week: body temperature: pounds of chocolate consumed in the past year: shoe size:
discrete discrete continuous continuous discrete
you want to find out whether caffeine mitigates the effect of alcohol on reacton time. to study this, you administer to your subjects a drink that is equivalent to three 12-ounce beers, followed by the equivalent of two cups of coffee. Then your subjects complete a simulated driving task in which they must follow a fixed speed limit while driving on a straight road. Wind periodically and randomly pushes the simulated vehicle right, left, or not at all. Speed is measured in miles per hour above or below the 60-mph speed limit, with 2 mph being the smallest unit on the scale. Suppose the first subject scores 5 mph, detemine the real limits of 5. The lower real limit is: the upper real limit is: when measuring weight on a scale that is accurate to the nearest .01 kilogram. what are the real limits for the weight of 68 kilograms? when measuring weight on a scale that is accurate to the nearest 0.1 kilogram, what are the real limits for the weight of 83 kilograms?
lower: 4.5 upper: 5.5 67.95-68.05 82.75-83.25
what is sampling error?
the natural occuring discrepancy that exists between a sample statistic and the corresponding population parameter.
a statistic is which of the following?
a characteristic of a sample.
Scientists are looking at the effects of global warming on clutches(nests) of sea turtle hatchling in different parts of the world. for a sample of clutch of turtles hatchling, suppose that data were collected on the following variables: temperature gender number of hatches turtle eggs number of unhatched turtle eggs location of turtles recognizing the measurements of scale of the data collected on each variable is importat because the type of data dictates the appropriate data summary methods and statistical procedures. which variable in the data set are measured using a nominal scale? which variable in the data set are measured using a ordinal scale? which variable in the data set are measured using a ratio scale?
nominal: location ordinal: gender group ratio: temp of incubation, number of hatched and unhatched eggs.
oxycotin is a naturally occuring brain chemical that is nicknamed the 'love hormone' because it seems to play a role in the foundation of social relationships such as mating pairs and social child bonding. a recent study demonstrated that oxycotin appears to increase people tendency to trust others. the independent variable is? the Dependent variable is?
the substance that is inhaled, either oxycotin or the inactive placebo. Whether the subjects are willing to give their money to the trustee.
The goal of an experimental research study is which of the following?
to demonstrate the existence of a cause-and-effect relationship between two variables.
four scales of measurement were introduced in this chapter: nominal, ordinal, interval, ratio. classify each of the following examples of scales as either nominal, ordinal, interval, or ratio.:
volume of a sada can: RATIO degrees around a circle: INTERVAL street address of a home in a neighborhood:Nominal satisfaction ratings:Ordinal
for the following scores find the value of each expression: X ---- 6 9 2 1
ΣX: 18 ΣX^2: 122 (squared) ΣX +1: 19 Σ(X+1): 22
A psychology professor wants to know whether age is related to memor quality in current first-year students at her small college. participants in the study complete an online memory task. the students are first shown a list of 60 words.etc. A: which of the following are variables in the study? B:what is the population in the study? C:what is the sample in the study? D:what is an example of a statistic in the study? E:what is an example of a parameter in the study? F:what is an example of the professor using descriptive statistics? G:what is an example of the professor using inferential statistics?
A: the students percentage of new unrelated words that are mistakenly thought to be on the original list. the students ages. B: the 500 first year students at the college. C: the 50 students that participated in the study. D: 12%, the average percent of new unrelated words that were mistakenly thought to be on the original list by the 50 students. E: The actual average percentage of new unrelated words that would be mistakenly recognized as being from the original list by the 500 first-year students. F: she reports that the average percent of new unrelated words that were mistakenly thought to be on the original list was 12%. G: She infers that if all 500 students had done the experiment, the results would show that an average of 12% (plus or minus sampling error) of new words were mistakenly identified as original words despite being completely unrelated to the words on the original list.
Researchers at the columbia University Medical Center in New York conducted a study designed to investigate the relationship between positive emotios, whic is known as positive effect, and coronary heart disease. Researchers measured the risk of coronary heart disease and the degree of expression of positive emotions of 1,739 healthy adults who participated in the study. The patients were then monitored for a period of 10yrs for incidence of coronary heart disease. The researchers found that patients who displayed more positive affect had a lower risk of heart disease. which of the following conclusions can you make in the basis of this study?
Positive effect is associated with a lower risk of coronary heart disease.