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SOPHIA_UNIT_1_STATISTICS_MILESTONE_2020 - University of Alabama SOPHIA_UNIT_1_STATISTICS_MILESTONE_2020 UNIT 1 — MILESTONE 1 Score 24/29 You passed this Milestone 24 questions were answered cor... rectly. 5 questions were answered incorrectly. 1 A research team conducts a survey to determine the area of land used for farming in Iowa. The team randomly selects house addresses and sends the survey by mail. Which type of sampling method is the research team using? Systematic random sampling Cluster sampling Multi-stage sampling Simple random sampling RATIONALE By choosing randomly from the house addresses all households should have an equal chance of being chosen. This would make it a simple random sample. CONCEPT Simple Random and Systematic Random Sampling 2 The following shows the Consumer Price Index (CPI) for the years 2000-2005. All of the values use a reference year of 1983. Which of the following is true about the CPI, based on the information? $100 in 1983 would be equivalent to $178 in 2001. $100 in 2002 would have been worth $189.70 in 1983. $100 in 2000 would be equivalent to $194.50 in 2005. $100 in 2003 would be equivalent to $183.70 in 1983. RATIONALE Recall the CPI gives us a measure of price changes over time and allows us to transform values in one year to another. The value of the CPI in the base year is 100. This means that for $100 in 1983 is equivalent to $178 in 2001. CONCEPT Index Number and Reference Value 3 At a school of 900 students, 20% have blue eyes. A student randomly selects 100 students and finds 17% of them have blue eyes. A second student takes another random sample of 90 students and finds 24% of them have blue eyes. Which of the following explains why there is a difference between the two percentages? The samples were not random samples. Random error; the numbers were different due to variability inherent in sampling. Both samples suffered from non-response bias. The sample sizes were both too small. RATIONALE When sampling, there is always some variability that occurs. So, although the sample values are different and not equal to the true overall proportion of 20%, since they were randomly chosen, the differences are simply due to the variability that comes from sampling and not due to some systematic bias. As the sample size increases we would expect these differences to get smaller. CONCEPT Random and Systematic Errors 4 The traffic volumes at a major intersection in New York were surveyed every day between one and four in the afternoon for a month to study the traffic patterns in the city. Which of the following types of bias affects the conclusions of the survey? Selection bias Non-response bias Response bias Deliberate bias RATIONALE Selection bias is when the mode of selection introduces a bias in the sample so that it is not representative of the population of interest. Since they only collected information from 1 to 4pm, this is a selection bias. CONCEPT Selection and Deliberate Bias 5 A scientist is conducting a study on the effect of eating chocolate and overall mood. They believe that gender is a significant factor. The participants are divided by gender. Then, within each group, participants are randomly assigned to consume either chocolate or a placebo and then rate their mood for the day. This experiment will run for two weeks. Which type of experimental design does this situation describe? Randomized Block Design Completely Randomized Design https://www.coursehero.com/file/64074477/SOPHIA-UNIT-1-STAT-MILESTONEpdf/ Case-Control Design This study resource was shared via CourseHero.comMatched-Pair Design RATIONALE Since women are randomly assigned chocolate or placebo, this is a completely randomized design. CONCEPT Randomized Block Design 6 Which of these statements best defines a stratified random sample? It is a sample where the population is first broken into groups and then elements are randomly selected, in proportion, from each group. It is a sample where every nth element of the population is selected in a sequence. It is a sample where the population is divided into roughly equal groups, and then elements are randomly selected from each group. It is a sample in which every element has the same chance of being selected from the total population. RATIONALE Recall that a stratified random sample is first broken up into homogenous groups called strata. From those strata a random sample is then chosen. CONCEPT Stratified Random and Cluster Sampling 7 Select the correct statement regarding experiments. A researcher can control the environment and observe the response. A researcher cannot control the environment but can observe the response. A researcher can control the environment but cannot observe the response. A researcher can neither control the environment nor observe the response. RATIONALE The defining part of experimental setting is that the researcher can control the setting and apply some treatment to observe how it affects an outcome of interest. CONCEPT Observational Studies and Experiments 8 Researchers want to study the effects of classical music and memory. One group of participants will take a memory test with classical music playing in the background, while the other group will take the memory test in complete silence. It is believed that age has an effect on memory. Which of the following would work best to test if classical music has an effect on memory? A matched-pair design experiment A case-control observational study A completely randomized design experiment A randomized block design experiment RATIONALE In order to control for age in the study, by matching participants on age they can control for the affect of age on the outcome. So a matched-pair design would be most appropriate. CONCEPT Matched-Pair Design 9 Jenae noticed that many of her co-workers would opt for the coffee that appeared to be most recently brewed, regardless of the flavor of the coffee offered. This leads her to believe that what she was witnessing was not really representative of everyone's true flavor preferences. She adapted her experimental study accordingly. Select one control in Jenae's experimental study. Jenae places condiments at random places throughout the kitchen. Jenae keeps the same amount of sugar and artificial sweetener at each location. Jenae monitors the habits of the co-workers who do not drink coffee. Jenae takes note of the frequency in which co-workers refill their coffee mugs. RATIONALE In an experiment, controls are when conditions are manipulated by the experimenter to keep them constant. If she keeps the same amount of sweetener at all locations, this would be an example of a control. CONCEPT Experimental Design 10 In a game, Rachel throws three bean bags, aiming for the hole in the wooden board. Which of the following best classifies the arrangement of bean bags? High accuracy and low precision Low accuracy and high precision Low accuracy and low precision https://www.coursehero.com/file/64074477/SOPHIA-UNIT-1-STAT-MILESTONEpdf/ High accuracy and high precision This study resource was shared via CourseHero.comRATIONALE The bean bags are not close to the hole and they are spread out. So they are not accurate or precise or we can say low accuracy and precision. CONCEPT Accuracy and Precision in Measurements 11 In 2007, 4% of people buying new cell phones purchased a bluetooth earpiece during the same transaction. In 2012, 28% of people buying new cell phones purchased a bluetooth earpiece during the same transaction. Of the following choices, what is correct about the growth of bluetooth sales? It rose by 120 percentage points. It rose by 24%. It rose by 12%. It rose by 24 percentage points. RATIONALE We can note that the absolute difference between 2007 and 2012 is 4% to 28% or 24 percentage points. To get the percent difference we take the absolute difference and divide by the initial value: So we can say that sales actually grew 600%. CONCEPT Using Percentages in Statistics 12 Rob sent an email survey to 2,000 cell phone owners asking about their satisfaction with their current plan. Only 256 people returned the survey and they were predominately 18-24 years old. Which of the following statements is true? The survey suffers from census issues because only 256 people responded. The survey likely has bias because the people who could not answer differ from those who did answer. Rob is ignoring the assumption that all survey participants will want to act independently. Rob included too many people on the survey list, affecting the data collected. RATIONALE In this survey there was a very low response rate with only 256 of the 2000. The characteristics of those who responded are different from non-responders. Since the responders and non-responders differ, we would worry about this affecting how they responded. CONCEPT Bias 13 Cindy measured and recorded the temperature of a liquid for an experiment. She used a poorly calibrated thermometer and noted the temperature as 100.5 degrees Fahrenheit. The actual temperature of the liquid was 95 degrees Fahrenheit. The percent error in her calculation is __________. 5.79% -4.08% 4.08% -5.79% RATIONALE Recall that the percent error is equivalent to the absolute difference divided by the actual value. If the absolute measure is 95 degrees and the observed measure is 100.5 degrees, then the absolute error is: So we calculate the percentage error to be: CONCEPT Absolute Change and Relative Change 14 A sports trainer is going to do an experiment on the effect of Vitamin D supplements and his athletes. He randomly assigns all of his patients to either take Vitamin D supplements or take a placebo. What type of experimental design does this situation illustrate? Matched-Pair Completely Randomized Simple Random Randomized Block RATIONALE Since all athletes are assigned treatment or control for vitamin D randomly without considering other factors, this is called a completely randomized design. CONCEPT Completely Randomized Design 15 A shoe retailer decides to record the styles and sizes of shoes that his customers choose. He records this data for an entire year by keeping track of his customers' purchases. Which statement accurately describes the type of data the shoe retailer is collecting? The shoe retailer is gathering available data because customers tell him which shoe sizes and styles they prefer. The shoe retailer is gathering raw data because he is recording shoe sizes and styles by himself. The shoe retailer is receiving raw data on shoe sizes and styles from nearby shoe companies. The shoe retailer is receiving available data on shoe sizes and styles from nearby shoe companies. RATIONALE Since the retailer is gathering the data himself, this would be an example of raw data. CONCEPT Data 16 Thttps://www.coursehero.com/file/64074477/SOPHIA-UNIT-1-STAT-MILESTONEpdf/ o compare the teaching methodologies of two of its eighth-grade math teachers, a school decides to compare student test scores from the two classes throughout the year. This study resource was shared via CourseHero.comWhich type of statistical study is the school conducting? Matched-pair design study Prospective observational study Meta-analysis Retrospective observational study RATIONALE A study which gathers data moving forward is called a prospective study. Since the data is gathered on students without controlling the setting moving forward, it is a prospective observational design. CONCEPT Prospective and Retrospective Studies 17 A researcher would like to determine which age groups (18-29, 30-49, 50-64, 65 or older) in the United States currently identify playing golf as their favorite pastime. Which statistical study would be most appropriate to answer this question? A census A survey A single-blind experiment A prospective observational study RATIONALE In order to obtain information about favorite pastimes, it would be best to solicit information from people directly by using a survey. CONCEPT Surveys 18 In a bolt-manufacturing factory, it is estimated that 6% of the bolts being manufactured will be defective, with a 3% margin of error. Choose the statement that correctly describes the confidence interval. The percentage of defective bolts is 6% or less. The percentage of defective bolts is between 3% and 9%. The percentage of defective bolts is between 3% and 6%. The percentage of defective bolts is 6% or more. RATIONALE Recall for a confidence interval, we take the point estimate +/- margin of error. Using this framework we take the point estimate of 6%, then add and subtract the margin of error, 3%. This gives us a CI of 3% to 9%. CONCEPT Margin of Error 19 A survey was conducted to find the frequency with which people go to the movies. A group of 120 people in a mall were asked about how often they go out for a movie and It was found that 36 people go to movies at least once in a month. Which of these is an example of descriptive statistics? 30% of the people surveyed in the mall go to movies at least once in a month. 30% of the people who reside in the county go to movies at least once in a month. 30% of the people who visited the mall go to movies at least once in a month. 30% of the people who reside in the city go to movies at least once in a month. RATIONALE Recall a descriptive statistic is a summary figure from a sample, which is the information at hand. From this survey a statistic would be 36 of 120 people or 30% go to the movies at least once in a month. CONCEPT Statistics Overview 20 Which of these random samples represents a representative sample of the systolic blood pressure of all patients in a hospital? The systolic blood pressure of 50 patients in the neurology department. The systolic blood pressure of 50 employees in the hospital. The systolic blood pressure of 50 children admitted in the hospital. The systolic blood pressure of 50 patients in the hospital. RATIONALE For a sample to be representative it needs to look like the entire set of interest. To look like all patients in the hospital, they should be randomly sampled from the entire population not simply the neurology department or children. Employees are not a part of the population of interest. CONCEPT Random & Probability Sampling 21 An insurance firm wants to estimate the percentage of senior citizens in a small town with approximately 2,534 residents. It asks a group of 85 randomly selected people in the town about their age. Select the statement that is TRUE. The sample is 85 people. The population is 2,534 people. The sample is 85 people. The population is 2,449 people. None of the answer choices are true. The sample is 2,534 people. The population is 85 people. RATIONALE Recall the entire set of interest is the population and a sample is a subset of that population. In this question the entire set is the 2534 residents, with the sample being the 85 that were chosen to be analyzed about their age. CONCEPT https://www.coursehero.com/file/64074477/SOPHIA-UNIT-1-STAT-MILESTONEpdf/ This study resource was shared via CourseHero.comSampling 22 A factory manufactures bolts. One of its employees, working in the quality control department, checks the first 20 bolts manufactured in a day for possible defects. This is what type of sampling? Stratified sampling Voluntary response sampling Convenience sampling Systematic sampling RATIONALE Recall that convenience samples are samples taken due to their ease of gathering information. Since they simply used the first 20 bolts, this is an example of that. Convenience samples are generally biased as they probably don't represent the entire set of interest. CONCEPT Convenience & Self-Selected Samples 23 The owner of a new store on Main Street wants to turn the boulevard outside into extra parking spaces because she is concerned about parking availability. She randomly selects 500 residents of the town to take a survey, and these individuals have confirmed their participation. One of the survey questions reads, “Many residents believe the lack of available parking on Main Street is a major problem, and extra spaces along the boulevard would help. Do you agree?" The store owner's survey could suffer from which type of bias? Nonresponse bias There is no evidence of bias in the way this survey is carried out. Response bias Selection bias RATIONALE By stating that many residents already believe parking is an issue and putting a response inside of the question, this is a good example of response bias. CONCEPT Nonresponse and Response Bias 24 A team of researchers want to measure the distance covered while driving compared to a car's driving speed. Which statement is correct? The speed of the car is an explanatory variable. The speed of the car is a confounding variable. The speed of the car is a dependent variable. The speed of the car is a response variable. RATIONALE The outcome is the response, dependent or y -variable. The variable that explains the response is the explanatory, independent or x-variable. In this case the explanatory variable is speed with distance being the response. CONCEPT Variables 25 A different coffee seller offered to sell coffee to Jenae's company for half the cost of their current brand. Jenae knew her co-workers were really partial to the coffee they drank now, so she decided to conduct a study to see if they noticed the difference in flavor. Her co-workers were convinced they would. To avoid any bias, Jenae had a friend provide each person with a sample and said that some had the new coffee and some did not. Not even Jenae knew who had which brand of coffee. Jenae's strategy is an example of a(n) ________. blind experiment completely randomized experiment randomized experiment matched-pair designed experiment RATIONALE Since participants and Jenae are unaware of what group they are in, regular or new coffee group, this is referred to as blinding in an experiment. When both participants and investigator or not aware, this is referred to as a double blind experiment. CONCEPT Blinding 26 Which of the following data types will be continuous? The letter grades students received on a class quiz The number of children younger than ten that visited a planetarium last week The total weight of apples harvested in the farm in a season The number of cars in 100 households RATIONALE The total weight of apples can take on any value and is therefore continuous. The other measures can only take on a limited number of values and are discrete. CONCEPT Discrete vs. Continuous Data 27 Nick designs a clinical trial to test a new anxiety medication by creating a control group and a treatment group. If he gives the medication to patients in the treatment group and not to the control group, some patients might find out that they're not being treated. To improve his study, Nick decides to give a sugar pill to the control group. The sugar pill is an example of a __________. variable of interest confounding variable placebo case control RATIONALE https://www.coursehero.com/file/64074477/SOPHIA-UNIT-1-STAT-MILESTONEpdf/ This study resource was shared via CourseHero.comWhen no active treatment is given to the control group, we refer to this as the placebo. CONCEPT Placebo 28 Melissa is conducting a survey of her classmates because her teacher wants the class to learn more about hygiene habits. Melissa has developed a list of 10 questions. “Do you brush your teeth every day?” is the first question she asks. Which type of question is Melissa asking? Open question Closed and binomial question Open and binomial question Closed question RATIONALE In this question, the responses are limited and there are only 2 responses. This would be a closed binomial question type. CONCEPT Question Types 29 A local gym conducts a survey among the people in a mall. Which survey question would have a qualitative response? Do you exercise daily? How much do you weigh, in pounds? What is the amount of weight you can bench press, in pounds? How many servings of fruits do you eat every day? RATIONALE Simply stating yes or no is simply descriptive and cannot be measured numerically or used in arithmetic, so it is qualitative. CONCEPT Qualitative and Quantitative Data © 2020 SOPHIA Learning, LLC. SOPHIA is a registered trademark of SOPHIA Learning, LLC. About Contact Us Privacy Policy Terms of Use https://www.coursehero.com/file/64074477/SOPHIA-UNIT-1-STAT-MILESTONEpdf/ This study resource was shared via CourseHero.com Powered by TCPDF (www.tcpdf.org) [Show More]

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