Intro Stats - Module 3 (Questions and Answers A+ Graded 100% Verified)

Intro Stats - Module 3 (Questions and Answers A+ Graded 100% Verified) A probability distribution, sometimes called a probability distribution function, tells us A. the probability of each outcome B. all the possible outcomes of a random experiment C. Both A and B D. none of the above Correct Answer: C. Both A and B Determine if the following variable represents a continuous or discrete random variable. "The numbers of songs on an mp3 player" Correct Answer: Discrete Random Variable True or False: Discrete outcomes (or discrete variables) are numerical values that you can list or count. Correct Answer: True The probability distribution of discrete outcomes can be displayed A. as a graph B. as a table C. as a density curve D. both A and B E. both A and C F. both B and C Correct Answer: D. both A and B True or False: The binomial probability model is useful in many situations with discrete-valued numerical variables (typically counts, whole numbers). Correct Answer: True True or False: A characteristic of a binomial model is that the number of trials is a fixed number. Correct Answer: True Which of the following is NOT a condition of the binomial distribution? A. There are two possible outcomes. B. There are a set number of trials, n. C. The trials are dependent. D. The probability of success is constant from trial to trial. Correct Answer: C. The trials are dependent Many numerical variables, in which researchers have historically been interested, have distributions that what model provides a close fit? Correct Answer: Normal model In the Normal curve, if the standard deviation is large, then the normal curve is Correct Answer: Wide and low In the Normal curve, if the standard deviation is small, then the normal curve is Correct Answer: Narrow and tall When you are finding probabilities with normal models, the most helpful step is to A. sketch the curve to represent the normal model B. shade in the region of interest C. label the curve appropriately D. all of the above, in that order Correct Answer: D. all of the above, in that order True or False: The standard Normal model has a mean of 1 and a standard deviation of 0. Correct Answer: False The standard normal model is an important concept because it allows us to find the probabilities of any normal model using Correct Answer: The z-score To convert a value to its z-score, take the data value and Correct Answer: Subtract the mean, then divide by the standard deviation We use the InverseNormal function when we want to find A. A measurement, given the probability B. A measurement, given the percentile C. A measurement, given the left area under the normal curve D. All of the above Correct Answer: D. All of the above TRUE OR FALSE. A sample is a collection of people or objects taken from the population of interest. Correct Answer: True A numerical value that characterizes some aspect of a population is called a Correct Answer: Parameter A numerical characteristic of a sample of data is called a Correct Answer: Statistic TRUE OR FALSE. We use parameters to estimate statistics. Correct Answer: False TRUE OR FALSE. An important difference between parameters and statistics is that parameters are knowable. Correct Answer: False TRUE OR FALSE. Statisticians have developed notation for keeping track of parameters and statistics. In general, Greek characters are used to represent population parameters. Statistics (estimates based on a sample) are represented by English letters. Correct Answer: True In which way(s) can bias (a tendency to produce an untrue value) enter a survey? A. From taking a sample that is not representative of the population B. From asking questions that do not produce a true answer C. From statistics that are naturally biased D. All of the above Correct Answer: D. All of the above TRUE OR FALSE. No matter how many different samples we take, the value of p (the population proportion) changes from sample to sample, but the value of p-hat is always the same. Correct Answer: False The probability distribution of p-hat has a special name: Correct Answer: Sampling distribution TRUE OR FALSE. Bias is measured using the center of the sampling distribution. It is the distance between the center and the population value. Correct Answer: True Which of the following condition(s) on the sample must be met for applying the Central Limit Theorem for estimating proportions in a population? A. Random and independent B. Large sample C. Big population D. All of the above Correct Answer: D. All of the above How can we tell if the sample size is big enough before applying the Central Limit Theorem? (Let n be the sample size and let p-hat be the proportion of the sample having the desired characteristic.) CHOOSE ALL THAT APPLY. A. n(p-hat) has to be less than or = to 10. B. n(p-hat) has to be greater than or = 10 AND n(1 - p-hat) has to be greater than or = to 10. C. There has to be at least 10 success and 10 failures. D. The sample size has to be at least 50. E. The sample size has to be at least 100. Correct Answer: B. n(p-hat) has to be greater than or = 10 AND n(1 - p-hat) has to be greater than or = to 10. C. There has to be at least 10 success and 10 failures. If a sample size is n = 100 and p-hat = 9%, is the sample size large enough to apply the Central Limit Theorem for Sample Proportions? Correct Answer: No