Math 105 Exam 1Written With Questions And Answers All Correct.

Statistics - correct answers the science of collecting, analyzing, and drawing conclusions from data a statistic - correct answers numerical summary of a sample parameter - correct answers numerical summary of a population representative sample - correct answers will have same characteristics of populations in the same proportions as they exist in population data - correct answers collection of number or other pieces of information to which meaning has been attached variable - correct answers A factor that can change in an experiment, type of information collected (can be quantitive or categorical) ex: heigh, annual profit, hair color subject - correct answers the entity that information is collected on (individual, participant object) person, business, animal bias - correct answers a systematic prejudice in one direction standard deviation - correct answers roughly the average distance of the observed/recorded values from their mean explanatory variable - correct answers - predictor - independent variable (variable that is supposed to cause a reaction) - denoted with x response variable - correct answers -outcome dependent variable (variable that reacts to the independent variable) - denoted with y within groups - correct answers measurements taken on same group participants: all participants receive treatment between groups - correct answers comparing results of groups that are comprised of different subjects in each group (that have not been paired) categorical - responses placed into a category - correct answers ordinal - there is an inherent order to categories: small, medium, large....strongly agree, agree, neutral, disagree, strongly disagree nominal - categories cannot be ordered green, purple, red quantitive variable - numerical info that represents a quantity - correct answers discrete - something that has been counted, "how many.", it cannot have a partial number: number of cars, number of pets continuous - something that has measure "how much" or "amount of": height, weight, age observational experiment - correct answers researchers observe or measure and record info as it naturally occurs IMPORTANT: observational studies NEVER identify causation randomized - correct answers researchers actively intervene by randomly assigning individuals to treatment groups prior to recording information - can sometimes identify causation and are def needed to prove it double blind is used in a randomized experiment because........ - correct answers its intended to eliminate/reduce bias simple random (sampling) - correct answers each subject and sample has an equal chance of being selected - use random number generator to pick ppl - can leave out ppl necessary for sampling stratified sampling - correct answers SOME subjects are taken from SOME clusters - dividing people into different subgroups of similar individuals and taken a few individuals from each strata - has representation systematic sampling - correct answers every "k^th" subject is selected. ex: every 5th subject is selected random digit dialing - correct answers use a sample frame of landline and cell phones, randomly select numbers to call multistage - correct answers uses combination of sampling methods example - stratified - stratified - cluster - stratified - stratified - cluster volunteer/self-select - correct answers individual response to an appeal such as a survey through news programs or website (researcher does not know/control who sees invitation) convince/haphazard - correct answers subjects are easy to access example: professor interviews just her students, someone talks to people to exit the mall cluster sampling - correct answers all subjects are taken from SOME clusters - divide similar people into clusters (for ex all people living on the same floor) - once identified, predetermined number of clusters are identified and all individuals are selected for sample sampling methods not used to draw statistically valid conclusions: - correct answers volunteer/self-select and convince/hapazard how do boxplots match to the 5# summary - correct answers draw a box from the first quartile to the third quartile. A vertical line goes through the box at the median. The whiskers go from each quartile to the minimum or maximum. how do outliers impact measures of center - correct answers they are either extremely high or extremely low they affect the mean and standard deviation good qualities of graphs: - correct answers 1. data/info should stand out clearly from background 2. there should be a clear labeling of title, each axis, scale of each axis 3. a source of data 4. minimal extra/unnecessary material Categorical variable graphs - correct answers - pie chart - bar chart - pictogram graphs for quantitive data - correct answers single variable -stem plot -histogram showing relationship between 2 variables - line graph/time series plot - scatterplot A study reported in the May 17, 2012 issues of The New England Journal of Medicine followed people for an average of 13 years and found that people who consumed two or more cups of coffee a day were less likely to die during the course of the study than those who drank no coffee. Was this study a randomized experiment or observational study? - correct answers observational A study reported in the May 17, 2012 issues of The New England Journal of Medicine followed people for an average of 13 years and found that people who consumed two or more cups of coffee a day were less likely to die during the course of the study than those who drank no coffee. Based on this study, can it be concluded that drinking coffee causes people to live longer? - correct answers no, a relationship does not mean causation A study reported in the May 17, 2012 issues of The New England Journal of Medicine followed people for an average of 13 years and found that people who consumed two or more cups of coffee a day were less likely to die during the course of the study than those who drank no coffee. The following two headlines actually appeared in news outlets. Which headline is more appropriate? - correct answers "Coffee positively associated with life expectancy" states that there is an association but does not imply causation Suppose you have 30 tomato plants and want to know if fertilizing them will help them produce more fruit. You randomly assign 15 of them to receive fertilizer and the remaining 15 to receive none. You otherwise treat the plants in an identical manner. Is this a randomized experiment or observational study & why? - correct answers randomized. the plants are randomly assigned to receive treatments In its March 3-5, 1995 issue, USA Weekend magazine asked readers to return a survey with a variety of questions about sex and violence on television. Of the 65,142 readers who responded, 97% were "very or somewhat concerned about violence on TV." Based on this survey, can you conclude that about 97% of all U.S. citizens are concerned about violence on TV? Why or why not? - correct answers No, because the sample does not represent the population of all U.S. citizens this sample only consist of those who read USA weekend and have strong enough opinions to reply. does not represent the us citizens You decide to conduct a new study at the college to measure the relationship between the amount of sleep a student gets per night and the student's GPA. To save time, you decide to only sample the members of your class and ask them how much sleep they had last night. Check all that are true. - correct answers This is not an example of a representative sample. The sample was taken only from members of your class, and this may not be representative of the entire college. This is not an example of a representative sample. The sample only looks at the last night's sleep, and this may not be representative of the usual number of hours the student sleeps. The U.S. Department of Agriculture (USDA) uses surveys to obtain important economic estimates. One USDA survey of 30 farmers found the average amount they will pay per planted acreof corn is $674.96 What is the population? - correct answers all US farmers The U.S. Department of Agriculture (USDA) uses surveys to obtain important economic estimates. One USDA survey of 30 farmers found the average amount they will pay per planted acreof corn is $674.96 What is the sample? - correct answers 30 US farmers The U.S. Department of Agriculture (USDA) uses surveys to obtain important economic estimates. One USDA survey of 30 farmers found the average amount they will pay per planted acreof corn is $674.96 What is the statistic? - correct answers Average of $674.96 cost per acre of corn planted Which measures represents a data value that is extremely different that the rest of the data? - correct answers Outlier Which of the following measures of center is most sensitive to outliers. - correct answers mean Which of the following is similar to the average distance of values from the mean? - correct answers standard deviation What is the mean, median, and mode of the following data set? - correct answers Mean = 24.2, Median = 27; Mode = 34 In the data set from the previous question, if the value 10 had been entered incorrectly as 100, what effect would it have on the standard deviation? - correct answers Standard deviation would increase Which of the following is used to display the 5# summary including outliers? - correct answers box plot look at chapter 7 assignment - correct answers ...