Statistics > SOPHIA Milestone > Sophia Statistics Unit 1 Milestone, Revised, answers/ Rationale. (All)

UNIT 1 — MILESTONE 1 Score 25/29 You passed this Milestone 25 questions were answered correctly. 4 questions were answered incorrectly. 1 Jenae noticed that many of her co-workers would opt fo... r 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 makes sure that the coffee in different pots is brewed at the same time. Jenae uses different locations in the kitchen for the coffee pots. Jenae monitors the habits of the co-workers who do not drink coffee. RATIONALE In an experiment, controls are when conditions are manipulated by the experimenter to keep conditions as consistent as possible. In this example Jenae brews coffee at the same time, so this is a control. CONCEPT Experimental Design I need help with this question2 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 Deliberate bias Response bias Non-response 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 I need help with this question 3 A new pet food product for small dogs has been developed to help with tooth decay. Fifty-two dogs participate in the study. Each dog owner picks a card from a standard deck out of a hat. If the card is red, their dog will be in the treatment group. If the card is black, their dog will be in the placebo group. Which experimental design was used? Case-Control Design Randomized Block Design Matched-Pair DesignCompletely Randomized Design RATIONALE Since all dogs are assigned treatment or control randomly by picking a card without considering other factors, this is called a completely randomized design. CONCEPT Completely Randomized Design I need help with this question 4 Sam counts how many people came to the local political meeting. He counts 72 people, but forgot about the 4 people sitting behind him. The percent error in his calculation is __________. -5.3% 50% -2.8% 5.6% RATIONALE Recall that the percent error is equivalent to the absolute difference divided by the actual value. If the actual number of people was 76, and the observed number of people was only 72, then the absolute error is: So we calculate the percentage error to be: CONCEPTAbsolute Change and Relative Change I need help with this question 5 In a study to assess the risk of obesity with the amount of time exercised per week, researchers matched each patient, in a sample of 500 people who are obese, with a person of the same ethnicity, gender, and age (along with other similar characteristics) who is not obese. The researchers asked the patients and their matches a series of questions, and then tracked eating and exercise habits regularly for several years. Which type of statistical study are the researchers conducting? Prospective study Retrospective study Case-control study Designed experiment RATIONALE Since the study collected information on people over several years moving forward, it is a prospective study design. CONCEPT Prospective and Retrospective Studies I need help with this question 6 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 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 gathering available data because customers tell him which shoe sizes and styles they prefer. 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 I need help with this question 7 The manager of an amusement park conducts a survey among the people visiting the park to learn their favorite rides. Out of 100 people randomly selected to complete the survey, 25 people have chosen not to participate. The manager's survey suffers from which of the following types of bias? There is no bias in the way this survey is carried out. Nonresponse bias Selection bias Response bias RATIONALE Since 75% of the people didn't respond to the survey, we would worry about nonresponse bias, which means those who didn't respond would produce a very different outcome than those who did respond. CONCEPT Nonresponse and Response Bias I need help with this question 8 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. None of the answer choices are true. The sample is 2,534 people. The population is 85 people. The sample is 85 people. The population is 2,449 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 Sampling I need help with this question 9 Which of the following data types will be continuous? The number of children younger than ten that visited a planetarium last week The letter grades students received on a class quiz The number of cars in 100 households The total weight of apples harvested in the farm in a season 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 I need help with this question 10 A study in which results are measured without intervention from the researcher is called a(n) __________. Pilot study Observational study Controlled experiment Simple random sample RATIONALE Recall that an observational study is one in which there is no control over the setting in any way. CONCEPT Observational Studies and Experiments I need help with this question 11 Choose the statement that accurately describes how a city government could apply systematic random sampling. Every resident is divided into groups, and 1,000 people are randomly selected to participate in a survey about city services. Every fifth person in a population is selected to participate in a survey about city services. Every resident in five neighborhoods is selected to participate in a survey about city services. Every individual over the age of 18 is selected to participate in a survey about city services.RATIONALE A systematic sample is when every nth element is chosen from the population. In this case, by choosing every 5th household, this makes is a systematic sample. CONCEPT Simple Random and Systematic Random Sampling I need help with this question 12 A pizza owner asked 50 customers to taste a new type of topping and found that 40 people liked its taste. Which of these is an example of descriptive statistics? 80% of all people like the taste of the pizza topping. 80% of the surveyed customers like the taste of the pizza topping. 80% of the people in the city where the pizza shop is located like the taste of the pizza topping. 80% of all the pizza shop's customers like the taste of the pizza topping. RATIONALE Recall a descriptive statistic is a summary figure which uses the sample information at hand. Using the sample information we know 40 of 50 people or 80% like the taste of the pizza topping. CONCEPT Statistics Overview I need help with this question 13 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 prospective observational studyA survey A census A single-blind experiment 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 I need help with this question 14 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? Completely Randomized Design Matched-Pair Design Case-Control Design Randomized Block Design RATIONALE Since women are randomly assigned chocolate or placebo, this is a completely randomized design. CONCEPT Randomized Block Design I need help with this question15 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. The sample sizes were both too small. Both samples suffered from non-response bias. 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 I need help with this question 16 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? Closed and binomial question Open question Open and binomial questionClosed 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 I need help with this question 17 The manager of a food company wants to conduct a survey to find out whether consumers like or dislike a new brand of soup that was recently launched. Which of the following data collection methods is mostly likely to get unbiased results? Ask distributors who supply the products to local retailers about the popularity of different soup brands. Ask the employees in the company which soup is the best. Ask customers who visit retailers within a 15 mile radius of the company headquarters. Ask customers who visit the grocery store nearest to the manager's house which soup they like the best. RATIONALE In order to get the best understanding of which soup is the most popular, they want to get a sense of what brands in general customers like. Although asking retailers doesn't directly contact customers, by asking all retailers about their customers they will better capture customers in general than simply asking those who are near the company headquarters or those who live near the manager. CONCEPT Bias I need help with this question 18 A trainer is studying the effects of vitamin D on his athletes. He has realized that there are many potential confounding factors, such as gender and age. To limit the effect of these confounding variables, he decided tofirst group two athletes together based on these variables (for example, two 21-year-old males). Then he randomly assigned one person to receive the vitamin D and the other to receive a sugar pill. What type of experimental design does this situation demonstrate? Matched-Pair Design Randomized Block Design Simple Random Design Completely Randomized Design RATIONALE By matching on age and gender this is called a matched-pair design. CONCEPT Matched-Pair Design I need help with this question 19 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 $189.70 in 2004 $100 in 2000 would be equivalent to $189.7 in 2004 $100 in 2002 would be equivalent to $189.70 in 2004 $100 in 2004 would have been worth 189.70 in 1983. RATIONALE Recall that the CPI allows us to transform values from some year to values in another year. The value of the CPI in the base year is 100. Since the CPI in 2004 is 189.7, this means that for $100 in the base year of 1983 is equivalent to $189.7 in 2004. CONCEPT Index Number and Reference Value I need help with this question 20 A local school newspaper's editor wants to survey students to determine the approval rating of the current student council president. How would the newspaper apply the cluster sampling method to find this information? The newspaper staff surveys every student in a randomly selected grade. The newspaper staff surveys 30 students from each grade in the school. The newspaper staff surveys random students from every grade in the school. The newspaper staff surveys only the female students in the entire school. RATIONALE Recall that sometimes natural arrangements or clusters form which generally are geographic. In this case, each grade level represents a cluster of students in a grade level. From each grade level or cluster, we then select arandom sample. CONCEPT Stratified Random and Cluster Sampling I need help with this question 21 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 a response 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 an explanatory 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 I need help with this question 22 A survey result shows that cell phone usage among teenagers rose from 63% in 2006 to 71% in 2008. Of the following choices, which statement about cell phone use among teenagers is true? Cell phone usage rose by 11.2 percentage points. Cell phone usage rose by 12.7%.Cell phone usage rose by 8%. Cell phone usage rose by 12.7 percentage points. RATIONALE We can note that the absolute difference between 2006 and 2008 is 63% to 71% or 8 percentage points. To get the percent difference we take the absolute difference and divide by the initial value: So we can say cell phone usage rose by 12.7%. CONCEPT Using Percentages in Statistics I need help with this question 23 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 hospital. The systolic blood pressure of 50 children admitted in the hospital. The systolic blood pressure of 50 employees in the hospital. The systolic blood pressure of 50 patients in the neurology department. 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 I need help with this question24 A local gym conducts a survey among the people in a mall. Which survey question would have a qualitative response? How many servings of fruits do you eat every day? Do you exercise daily? What is the amount of weight you can bench press, in pounds? How much do you weigh, in pounds? 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 I need help with this question 25 A poll was conducted two weeks before an election and showed that the incumbent would win with 54% of the vote, with a 3% margin of error. What is the confidence interval for this poll? 51% to 57% 54% - 3% 54% + 3% 48% to 60%RATIONALE Recall for a confidence interval, we take the point estimate +/- margin of error. Using this framework we take the point estimate of 54%, then add and subtract the margin of error, 3%. This gives us a CI of 51% to 57%. CONCEPT Margin of Error I need help with this question 26 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? Convenience sampling Systematic sampling Stratified sampling Voluntary response 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 I need help with this question 27 Jenae's study ignored the fact that only some of her coffee choices had caffeine, even though her co-workers preferred caffeinated coffee. Therefore, Jenae decided to label one type of decaffeinated coffee as having caffeine to see what would happen.As she anticipated, this coffee became more popular with her co-workers, and they claimed that the extra boost of caffeine helped them focus on their work. The growing popularity of the decaffeinated coffee among co-workers, under the false impression that it gave them extra caffeine, is an example of ________. a control group the placebo effect a treatment group a case-control study RATIONALE Since no treatment of caffeine was given to these participants in the control group and they reported an effect, this is what we refer to as the placebo effect. CONCEPT Placebo I need help with this question 28 A hunter is practicing his aim using a practice target. He takes 5 shots. All 5 shots hit the target, but they do not hit or surround the bullseye. In addition, all 5 shots are very spread apart on the target. Classify the hunter's accuracy and precision. Low accuracy and high precision High accuracy and high precision Low accuracy and low precision High accuracy and low precisionRATIONALE Since the arrows fall away from the bullseye and are spread out we would classify this as low accuracy and low precision. CONCEPT Accuracy and Precision in Measurements I need help with this question 29 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. Jenae provided each person with a sample and said that some had the new coffee and some did not. Only Jenae knew who had which brand of coffee. Jenae's strategy is an example of a(n) ________. matched-pair designed experiment randomized experiment blind experiment completely randomized experiment RATIONALE Since participants are unaware of what group they are in, regular or new coffee group, this is referred to as blinding in an experiment. CONCEPT Blinding I need help with this question © 2020 SOPHIA Learning, LLC. SOPHIA is a registered trademark of SOPHIA Learning, LLC. About Contact Us Privacy Policy Terms of Use [Show More]

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