Statistics Chapter 1 Questions & Answers

Statistics Chapter 1 Questions & Answers A study is conducted to measure children's growth rates without any treatment applied to the children. What best classifies this study? - ANSWER: Observational Study A study of an association between which ear is used for cell phone calls and whether the subject is left-handed or right-handed began with a survey e-mailed to 5000 people belonging to an otology online group, and 717 surveys were returned. (Otology relates to the ear and hearing.) What percentage of the 5000 surveys were returned? Does that response rate appear to be low? In general, what is a problem with a very low response rate? - ANSWER: 717 / 5000 = 0.1434 0.1434 x 100 = 14% Of the 5000 surveys, 14% were returned. This response rate APPEARS to be low What is a problem with a very low response rate? It creates a serious potential for getting a biased sample that consists of those with a special interest in the topic. Cluster Sampling - ANSWER: We first divide the population area into sections (or clusters), then randomly select some of those clusters, and then choose ALL the members from those selected clusters. Completely Randomized Design - ANSWER: For a completely randomized design, subjects are assigned to different treatment groups through a process of random selection. Continuous (numerical) data - ANSWER: Result from infinitely many possible values that correspond to some continuous scale that covers a range of values without gaps, interruptions, or jumps. Example: In a classroom of 30 children ages range from 9-11. What is the Continuous data in this situation? When there is a range of information it is Continuous. Therefore the age range: 9 to 11 is the continuous data. Control Effects of Variables - ANSWER: Don't let other variables interfere with the effects you want to see Convenience Sampling - ANSWER: Simply use results that are the easiest to get. Cross-sectional study - ANSWER: data are observed, measured, and collected at one point in time. Determine if the following statement represents a meaningful ratio, so the ratio level of measurement apples. A movie with a 4-star rating is twice as good as one with a 2-star rating. - ANSWER: The ratio level of measurement does not apply. The ratio is not meaningful because the stars don't measure or count anything. Difference between star values are not meaningful. Determine whether each of the following is a simple random sample and a random sample.