Question 10 4.5 pts A teacher at NC State is interested in how often students use their cell phones during class. She watches a selected group of students at their desks during class. This study would best be described as: 0 An observational study. 0 A survey. 0 A sample. 0 An experiment. Question 11 4.5 pts Which of the following sample designs will result in a sample that is most representative of the population, or contain the least amount of bias? 0 300 math students in Math II are given a number. Ten numbers are chosen randomly and each winning number will get a $15 gift card to Target. 0 A teacher wishes to know how his students at his high school feel about online homework. He emails a survey about the issue to a random sample of his students. 0 Dancing with the Stars asks its viewers to text their vote for their favorite dancers. O The school calls every person with a landline to ask the parents their opinion of using online textbooks over hardback textbooks. Not everyone in the school has a landline. Question 12 4.5 pts A study is designed to determine whether or not taking four years of math in high school helps students' acceptance chances at NC State. - At a certain high school 300 students were not permitted to take a fourth year of math and 300 students were required to take a fourth year of math. - In comparing the acceptance rates of the 600 students at NC State it is noted that the average entrance rate for those who took a fourth year of math is higher than those who took three years of math. - Based on this experiment, guidance counselors began recommending a fourth year of math for college bound students. Which of the following is not true? 0 A more meaningful study would be to do an observational study on an SRS of students who have already signed up for a third of fourth year of math. O This study proves that taking four years of math in high school gives students a higher acceptance rate into NC State. 0 No conclusion can be made about the relationship between taking four years of math and acceptance rates. 0 This is an experiment, not an observational study. Question 13 4.5 pts Which of the following is true regarding the sample size when estimating a population mean or proportion? O The size of the sample does not matter as long as it is a simple random sample. O The larger the sample size the more accurate the estimate will be. 0 The smaller the sample size the more accurate the estimate will be. 0 The larger the sample size the more likely it is to over or underestimate the population mean or proportion. Question 14 4.5 pts The following 12 sample proportions were taken from a group of 25 students. The proportion represents the proportion of students who wear glasses to drive or watch TV: 0.73 0.55 0.63 0.25 0.88 0.61 0.70 0.33 0.54 0.50 0.47 0.35 What is the mean of all of the proportions that were gathered in the table above? 0 0.565 O 0.5 O 0.675 O 0.545 Question 15 4.5 pts Sample proportions of size ten were taken from a group of students. Students were asked if they wore glasses while watching TV. The proportion that wore glasses while watching TV was recorded. The standard deviation of the data is 0.19. The margin of error can be given by the formula M07173.\" of error = 2 X i, where sis the standard deviation and n is the sample size. What is the margin of error for the data collected? O 0.5 o 0.565 o 0.12 O 0.038 Question 8 4.5 pts At the stadium for the Pittsburgh Steelers the owners decide to survey the opinions of bleacher fans. They plan to select every fth fan entering the stadium one Sunday afternoon. What is the weakness is using this sampling method? 0 The weakness here is that not every bleacher fan has an equal opportunity of being chosen. Only every 50th person has a chance. Every other fan is left out. 0 There is no weakness. This is a an excellent method of collecting a simple random sample. All people entering the stadium have an equal chance of being selected. 0 There is no weakness, this is an example of a simple random sample. 0 The weakness is that only the people that are volunteering to be part of the sample have a chance of being selected. Question 9 4.5 pts Which of the following is not important when designing an observational study or experiment in statistics? O All samples must simple random samples. No other type will work. 0 Interpret the results to draw a conclusion. 0 Formulate a question that can be answered with data that is collected. 0 Make a design on how the data will be collected