Sophia Learning STAT1001: Introduction to Statistics UNIT 1 — MILESTONE 1 Answered 2024/45.

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1 25/29  that's 86% RETAKE  25 questions were answered correctly. 4 questions were answered incorrectly. Jenae is able to purchase a different brand of coffee for half the price from a new s... upplier. She anticipated that her co-workers would object to switching to the new brand, as they were really partial to the coffee they have been drinking so far. Indeed, when offered a taste test of the old brand versus the new brand, her co-workers unanimously rejected the new brand. Jenae's boss, Steven, pointed out that this result was most likely due to the fact that the taste test was not ________. ●  UNIT 1 — MILESTONE 1 25/29 CONCEPT → Blinding 2  ● ● controlled # blinded ● randomized ● replicated overfilled. An employee randomly selects 100 bags and finds that 5% are overfilled. A second employees takes another random sample of 250 bags and finds that 2% are overfilled. Which of the following explains why there is a difference between the two percentages?  ● The samples were not random samples. ● The sample sizes were both too small, which is why they both obtained figures different than 3% # Random error; the numbers were different due to variability inherent in sampling. ● Both samples suffered from nonresponse bias. CONCEPT → Random and Systematic Errors 3 Jenae used an aspect of experimental design known as ________ when she took these actions. ●  CONCEPT → Experimental Design 4  # ● control ● randomization ● random assignment ● replication Mike wants to find out the approximate income for professors in Michigan. He decides to randomly select 50 professors who work for a college or university in Michigan and obtain their salaries. What are the sample and the population of Mike's study? ● The professors in Michigan are the sample, and all the professors in the United States are the population. ● The 50 professors that Mike interviews are his sample, and the professors that Mike does not interview are the population. CONCEPT → Sampling  ● All of the professors who work in Michigan are the sample, and the 50 professors that Mike interviews are the population. # The 50 professors that Mike interviews are his sample, and all of the professors who work in Michigan are the population. https://app.sophia.org/spcc/introduction-to-statistics-2/milestone_take_feedbacks/33730228 6/12/24, 11:12 AM Page 7 of 44 5 A student group on a college campus wanted to create a survey about parking availability on campus. The student group randomly selected 300 students to take the survey. One of the questions read, “Many students believe the lack of available parking is a major problem. Do you agree or disagree?” Of the 300 students that took the survey, 285 surveys were returned. This survey will most likely suffer from which of the following types of bias? RATIONALE ●    ● Selection bias # Non-response bias ● Response bias ● There is no bias in the way this survey is carried out. https://app.sophia.org/spcc/introduction-to-statistics-2/milestone_take_feedbacks/33730228 6/12/24, 11:12 AM Page 8 of 44 CONCEPT → Nonresponse and Response Bias 6 By putting a response inside of the question which may lead survey participants to a given response, this is a good example of response bias. Report an issue with this question The administrator of a hospital conducted a survey among patients in the cardiology wing to determine service levels of the nursing staff in the hospital. Which of the following explains how the results of the survey could be biased? ● ● The sample does not include the staff members of the hospital. https://app.sophia.org/spcc/introduction-to-statistics-2/milestone_take_feedbacks/33730228 6/12/24, 11:12 AM Page 9 of 44 CONCEPT → Bias RATIONALE Since the patients asked are only from the cardiology unit, it might not represent patients in all sections of the hospital. It would be better to include all areas of the hospital. Report an issue with this question  # The sample does not include all the patients in the hospital. ● The sample does not include the board members of the hospital. ● The sample does not include the doctors of the hospital. https://app.sophia.org/spcc/introduction-to-statistics-2/milestone_take_feedbacks/33730228 6/12/24, 11:12 AM Page 10 of 44 7 A local bakery conducts a phone survey to find the most popular types of cakes. They selected 100 random phone numbers from the local telephone directory and called them. This type of sampling method is called __________. RATIONALE By choosing randomly from the directory, all people should have an equal chance of being chosen. This would make it a simple random ●   # Simple random sampling ● Systematic random sampling ● Convenience sampling ● Multi-stage sampling https://app.sophia.org/spcc/introduction-to-statistics-2/milestone_take_feedbacks/33730228 6/12/24, 11:12 AM Page 11 of 44 CONCEPT → Simple Random and Systematic Random Sampling 8 sample. Report an issue with this question A factory manufactures motorcycles. One of its employees, working in the quality control department, checks the first 10 and the last 10 motorcycles manufactured in a day. This is what type of sampling? ●   ● Systematic sampling ● Stratified sampling # Convenience sampling https://app.sophia.org/spcc/introduction-to-statistics-2/milestone_take_feedbacks/33730228 6/12/24, 11:12 AM Page 12 of 44 CONCEPT → Convenience & Self-Selected Samples 9 RATIONALE Recall that convenience samples are samples taken due to their ease of gathering information. Since they simple used the first and last 10, this is an example of that. Convenience samples are generally biased as they probably don't represent the entire set of interest. Report an issue with this question Researchers want to test the effects of a new weight loss program. They believe that gender is a significant factor. The participants are divided by gender. Then, within each group, participants are randomly assigned to either the treatment or control group. Which of the following would be the most effective to test the effects of the new weight ● ● Voluntary response sampling https://app.sophia.org/spcc/introduction-to-statistics-2/milestone_take_feedbacks/33730228 6/12/24, 11:12 AM Page 13 of 44 CONCEPT → Randomized Block Design loss program? RATIONALE Since people are first put into gender and then are assigned treatment or control randomly this is called a randomized block design. Report an issue with this question  ● A completely randomized design experiment ● A longitudinal observational study # A randomized block design experiment ● A matched-pair design experiment https://app.sophia.org/spcc/introduction-to-statistics-2/milestone_take_feedbacks/33730228 6/12/24, 11:12 AM Page 14 of 44 10 Which of the following data types will be continuous? RATIONALE For data to be continuous, it must be able to ●   ● The number of books in the school library ● The letter grade Tyron received on an English test ● The number of students who like chocolate or strawberry or vanilla ice-cream flavors # The amount of snow that fell last night https://app.sophia.org/spcc/introduction-to-statistics-2/milestone_take_feedbacks/33730228 6/12/24, 11:12 AM Page 15 of 44 CONCEPT → Discrete vs. Continuous Data 11 take on any value inside of an interval. The amount of snow that falls can be any value and is therefore continuous. All the other measures can only take on a limited number of values. Report an issue with this question 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 ________. ●  https://app.sophia.org/spcc/introduction-to-statistics-2/milestone_take_feedbacks/33730228 6/12/24, 11:12 AM Page 16 of 44 CONCEPT → Placebo 12 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. Report an issue with this question Jessica uses a poorly calibrated stopwatch to note the finish time of a relay race. She noted the time as 125 seconds, whereas the actual  ● ● a case-control study ● a treatment group # the placebo effect ● a control group https://app.sophia.org/spcc/introduction-to-statistics-2/milestone_take_feedbacks/33730228 6/12/24, 11:12 AM Page 17 of 44 time taken was 120 seconds. The percent error in Jessica's calculation is __________. RATIONALE Recall that the percent error is equivalent to the absolute difference divided by the actual value. If the actual measure is 120 seconds and the observed measure is 125 seconds, then the absolute difference is: So we calculate the percentage error to be:  ● -4.0% ● 4.0% # 4.2% ● -4.2% https://app.sophia.org/spcc/introduction-to-statistics-2/milestone_take_feedbacks/33730228 6/12/24, 11:12 AM Page 18 of 44 CONCEPT → Absolute Change and Relative Change 13 Report an issue with this question It’s Saturday afternoon, and Denise is going shopping. She stops by a department store because she needs a new pair of shoes. She has picked out three styles that she likes. The store associate asks, “What is your shoe size?” Which type of question has the store associate asked? ●   # Closed question ● Open and binomial question ● Open question https://app.sophia.org/spcc/introduction-to-statistics-2/milestone_take_feedbacks/33730228 6/12/24, 11:12 AM Page 19 of 44 CONCEPT → Question Types 14 RATIONALE Recall a closed question has only a limited number of responses. Since she can only answer with her shoe size, this would be a closed question. Report an issue with this question 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 ● ● Closed and binomial question https://app.sophia.org/spcc/introduction-to-statistics-2/milestone_take_feedbacks/33730228 6/12/24, 11:12 AM Page 20 of 44 CONCEPT → Prospective and Retrospective Studies 15 researchers conducting? RATIONALE Since the study collected information on people over several years moving forward, it is a prospective study design. Report an issue with this question A hunter is practicing his aim using a practice   ● ● Retrospective study ● Designed experiment # Case-control study ● Prospective study https://app.sophia.org/spcc/introduction-to-statistics-2/milestone_take_feedbacks/33730228 6/12/24, 11:12 AM Page 21 of 44 CONCEPT 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. RATIONALE Since the arrows fall away from the bullseye and are spread out we would classify this as low accuracy and low precision.  ● Low accuracy and high precision ● High accuracy and high precision ● High accuracy and low precision # Low accuracy and low precision https://app.sophia.org/spcc/introduction-to-statistics-2/milestone_take_feedbacks/33730228 6/12/24, 11:12 AM Page 22 of 44 → Accuracy and Precision in Measurements 16 Report an issue with this question 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 to first 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? ● ● Simple Random Design ● Completely Randomized Design https://app.sophia.org/spcc/introduction-to-statistics-2/milestone_take_feedbacks/33730228 6/12/24, 11:12 AM Page 23 of 44 CONCEPT → Matched-Pair Design 17 RATIONALE By matching on age and gender this is called a matched-pair design. Report an issue with this question The following shows the Consumer Price Index (CPI) for the years 2000-2005. All of the values use a reference year of 1983.  ● ● Randomized Block Design # Matched-Pair Design https://app.sophia.org/spcc/introduction-to-statistics-2/milestone_take_feedbacks/33730228 6/12/24, 11:12 AM Page 24 of 44 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 2000 would be equivalent to $194.50 in 2005. ● $100 in 2003 would be equivalent to $183.70 in 1983. https://app.sophia.org/spcc/introduction-to-statistics-2/milestone_take_feedbacks/33730228 6/12/24, 11:12 AM Page 25 of 44 CONCEPT → Index Number and Reference Value 18 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. Report an issue with this question A survey result shows that cell phone usage among teenagers rose from 63% in 2006 to 71% in 2008. Of the following choices, which two statements about cell phone use among teenagers is true? ● ● $100 in 2002 would have been worth $189.70 in 1983. https://app.sophia.org/spcc/introduction-to-statistics-2/milestone_take_feedbacks/33730228 6/12/24, 11:12 AM Page 26 of 44 RATIONALE We can note that the absolute difference  ● Cell phone usage rose by 12.7 percentage points. Cell phone usage rose by 8%. ● Cell phone usage rose by 8 percentage points. Cell phone usage rose by 11.2%. ● Cell phone usage rose by 11.2 percentage points. Cell phone usage rose by 12.7%. # Cell phone usage rose by 8 percentage points. Cell phone usage rose by 12.7% https://app.sophia.org/spcc/introduction-to-statistics-2/milestone_take_feedbacks/33730228 6/12/24, 11:12 AM Page 27 of 44 CONCEPT → Using Percentages in Statistics 19 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%. Report an issue with this question James conducts a survey to study the relationship between cell phone use and grades earned during the fall semester. James suspects that there might be a lot of other factors that affect grades besides cell phones. Which of the following could be a confounding variable in James's study? ●  https://app.sophia.org/spcc/introduction-to-statistics-2/milestone_take_feedbacks/33730228 6/12/24, 11:12 AM Page 28 of 44 CONCEPT → Variables RATIONALE Recall a confounding variable is related to the outcome and explanatory variable and is not accounted for in a study. Although cell phone usage may be related to grades, by not accounting for study time, which is most likely related to grades, it confounds the results between cell phone usage and grades. So we can say study time is a confounding variable. Report an issue with this question  ● Grade earned during the fall semester # Time spent studying ● Time spent using a cell phone ● Grade earned during the spring semester https://app.sophia.org/spcc/introduction-to-statistics-2/milestone_take_feedbacks/33730228 6/12/24, 11:12 AM Page 29 of 44 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 random students from every grade in the school. ● The newspaper staff surveys only the female students in the entire school. ● The newspaper staff surveys every student in the lunchroom and science room. https://app.sophia.org/spcc/introduction-to-statistics-2/milestone_take_feedbacks/33730228 6/12/24, 11:12 AM Page 30 of 44 CONCEPT → Stratified Random and Cluster Sampling 21 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 newspaper staff surveys every student in a randomly selected grade. CONCEPT → Completely Randomized Design the placebo group. Which experimental design was used?  ● Case-Control Design ● Matched-Pair Design ● Randomized Block Design # Completely Randomized Design 22 A travel agency contacted a department store and obtained the list of all people who made purchases using their credit cards at the store in the last month. The agency then surveyed a random sample from the list, calling them to ask their preference for air travel or train travel for taking holidays. Which of the following types of bias affects the conclusions of the survey? ●   ● Deliberate bias # Selection bias ● Non-response bias ● Response bias https://app.sophia.org/spcc/introduction-to-statistics-2/milestone_take_feedbacks/33730228 6/12/24, 11:12 AM Page 33 of 44 CONCEPT → Selection and Deliberate Bias 23 introduces a bias in the sample so that it is not representative of the population of interest. Since they only collected information from those using their credit card at a department store, this does not represent how people travel in general and is therefore an example of selection bias. Report an issue with this question 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? ●  https://app.sophia.org/spcc/introduction-to-statistics-2/milestone_take_feedbacks/33730228 6/12/24, 11:12 AM Page 34 of 44 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  ● 30% of the people who reside in the county 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. # 30% of the people surveyed in the mall 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. https://app.sophia.org/spcc/introduction-to-statistics-2/milestone_take_feedbacks/33730228 6/12/24, 11:12 AM Page 35 of 44 CONCEPT → Statistics Overview 24 least once in a month. Report an issue with this question A study in which results are measured without intervention from the researcher is called a(n) __________. RATIONALE ●   ● Pilot study ● Controlled experiment # Observational study ● Simple random sample CONCEPT → Observational Studies and Experiments 25 Recall that an observational study is one in which there is no control over the setting in any way. Report an issue with this question The owner of a pizza parlor called every fifth person who ordered pizza last week to rate the pizza. What type of statistical study is this? ●   # A survey ● An observational study ● A census CONCEPT → Surveys 26 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? ● ● An experiment ● 48% to 60% ● 54% + 3% → Margin of Error 27 Which statement accurately describes the type  ● ● 54% - 3% # 51% to 57% of data the retail brand is using?   ● The census is an example of available data because the government provides it. ● The census is an example of raw data because the government provides it. ● The retail brand is relying on available data because customers provide information to the census. # The retail brand is relying on raw data because it has to ask for permission to use the census. → Data 28 Which survey question would have a qualitative response? ●   ● What is the amount of weight you can bench press, in pounds? # Do you exercise daily? → Qualitative and Quantitative Data 29 Which of these random samples represents a representative sample of the systolic blood pressure of all patients in a hospital? ● ● How many servings of fruits do you eat every day? ● How much do you weigh, in pounds? 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 ● 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 patients in the hospital. ● The systolic blood pressure of 50 children admitted in the hospital. [Show More]

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