INTRO TO STATS Milestone 1 Sophia EXAM ELABORATIONS QUESTIONS AND ANSWER (PASSED)

You passed this Milestone 24 questions were answered correctly. 5 questions were answered incorrectly. 1 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 high precision  High accuracy and low precision  Low accuracy and high precision  Low accuracy and low precision RATIONALE 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 2 Which of these random samples represents a representative sample of the number of students who enjoy science class?  30 students who received high grades in their science class last semester  30 students who participated in the science fair  30 students in the lunchroom  Your text here 1 30 students who failed science class last year RATIONALE For a sample to be representative it needs to look like the entire set of interest. By choosing students in the lunchroom, they are drawing upon all students in the school and not an unrepresentative one. CONCEPT Random & Probability Sampling 3 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?  An observational study  An experiment  A survey  A census RATIONALE Since the owner asked patrons about the pizza and gathered information from them, this is an example of a survey. CONCEPT Surveys 4 “Ugh,” Daniel says as he notices an office memo on his desk. It had been a fun weekend, and Monday morning came much too soon. He goes to the kitchen to refill his coffee mug. On the way, he runs into Sean, who asks, “How do you feel about the new office dress code?” Which type of question has Sean asked?  Closed question  Open question  Open and binomial question  Closed and binomial question RATIONALE In an open question, a responder can answer how they like. Since Sean can respond how he wants, this is an open question. CONCEPT Question Types 5 Which of the following data types will be continuous?  The letter grade Tyron received on an English test  The number of books in the school library  The number of students who like chocolate or strawberry or vanilla ice-cream flavors  The amount of snow that fell last night RATIONALE For data to be continuous, it must be able to 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. CONCEPT Discrete vs. Continuous Data 6 Scientists want to test a new pair of running shoes. A speed test is performed with two separate groups of participants. The treatment group will wear the new pair of running shoes, while the control group will not. It is believed that age and height may affect speed. Which of the following would be most effective in controlling the confounding variables, such as age and height, in this study?  A completely randomized design experiment  A retrospective observational study  A longitudinal observational study  A matched-pair design experiment RATIONALE In order to control for variables that may affect the study, a matched pair design which matches as closely as possible for those variables would best control for their effects. CONCEPT Matched-Pair Design 7 A local gym conducts a survey among the people in a mall. Which survey question would have a qualitative response?  How much do you weigh, in pounds?  What is the amount of weight you can bench press, in pounds?  Do you exercise daily?  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 8 Aaron has designed a trial to test a new energy drink. Fifty individuals in the treatment group try the new energy drink every day for two weeks, and they describe a moderate increase in their energy levels. Fifty individuals in the control group drink sugar water every day for two weeks, and they describe a significant increase in their energy levels. What has Aaron observed?  A sampling error  The margin of error  The placebo effect  A confounding variable RATIONALE Since no treatment 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 9 A study in which results are measured without intervention from the researcher is called a(n) __________.  Controlled experiment  Observational study  Simple random sample  Pilot study 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 10 An appliance store manager noted that the sales of home appliances contributed 74% of the store's profits in the year 2010 and 82% in the year 2011. Of the following choices, which statement about home appliance sales is true?  Home appliance sales increased profits by 8%.  Home appliance sales increased profits by 8 percentage points.  Home appliance sales increased profits by 9.75 percentage points.  Home appliance sales increased profits by 9.75%. RATIONALE We can note that the absolute difference between 2010 and 2011 is 74% to 82% or 8 percentage points. To get the percent difference we take the absolute difference and divide by the initial value: So we can say sales actually grew by 10.8%. CONCEPT Using Percentages in Statistics 11 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 the surveyed customers like the taste of the pizza topping.  80% of all people like the taste of the pizza topping.  80% of all the pizza shop's 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. 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 12 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?  Multi-stage sampling  Systematic random sampling  Simple random sampling  Cluster 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 13 To test the effectiveness of a new, cholesterol-lowering drug, a group of researchers recruits 200 volunteers with high cholesterol to take part in a study. The researchers place the numbers 1 through 200 in a hat and have each participant select a number. Those who picked an odd number receive the new drug, while those who picked an even number receive a placebo. Which experimental design are the researchers using?  Matched-Pair Design  Randomized Block Design  Completely Randomized Design  Representative Sample Design RATIONALE When all patients are assigned treatment or control randomly without considering other factors, this is called a completely randomized design. CONCEPT Completely Randomized Design 14 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 more.  The percentage of defective bolts is between 3% and 9%.  The percentage of defective bolts is 6% or less.  The percentage of defective bolts is between 3% and 6%. 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 15 A grocery store owner asked the first 20 children who visited the store one day about their favorite snack. This is what type of sampling?  Systematic sampling  Stratified sampling  Voluntary response sampling  Convenience sampling RATIONALE Recall that convenience samples are samples taken due to their ease of gathering information. Since he simply asked the first 20 children, 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 16 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 only the female students in the entire school.  The newspaper staff surveys random students from every grade in the school.  The newspaper staff surveys every student in a randomly selected grade.  The newspaper staff surveys 30 students from each grade in the 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 a random sample. CONCEPT Stratified Random and Cluster Sampling 17 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?  Time spent using a cell phone  Time spent studying  Grade earned during the fall semester  Grade earned during the spring semester 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. CONCEPT Variables 18 To 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. Which type of statistical study is the school conducting?