Math 221 Final Study Statistics Questions with 100% Correct Answers

Difference between categorical and quantitative data Correct Answer Quantitative variables provide numerical information. Categorical variables yield data that can only be considered as categories. Differences in the definitions of a Parameter, Population, Statistic and a Sample Correct Answer Parameter: Numbers that summarize data from a population Population: Entire collection of a group Statistic: The probability of obtaining a result or numbers that summarize the data from a sample Sample: A manageable group of items The different Types of Random Sampling Methods Correct Answer Simple Random Sample (SRS): a random selection taken from a population Systematic Sample: every kth item in the population, beginning at a random starting point Cluster Sample: all items in one or more randomly selected clusters, or blocks Stratified Sample: divides data into similar groups and an SRS is taken from each group Convenience Sample: is one easily obtained in a less-than-systematic way and should be avoided whenever possible Why do we use random sampling? Correct Answer It is more accurate to get a sample that is random because it represents the population better in the study. How do you calculate a z -Score and probabilities from a normal distribution? Correct Answer Use the equation z=x−μ/σ Use the probability applet and appropriately shade the area (left, center, right) given. How do you use the 68-95-99.7 Rule? Correct Answer 68% of the data will lie within 1 standard deviation of the mean 95% of the data will lie within 2 standard deviations of the mean 99.7% of the data will lie within 3 standard deviations of the mean. This is called the 68-95-99.7% Rule for Bell-shaped Distributions. Some statistics books refer to this as the Empirical Rule. What does percentile means? Correct Answer A number such that a specified percentage of the data are at or below this number. For example, the 99th percentile is a number such that 99% of the data are at or below this value.