Statistical Methods Exam I Review

Transcription

1 Statistical Methods Exam I Review Professor: Dr. Kathleen Suchora SI Leader: Camila M. DISCLAIMER: I have created this review sheet to supplement your studies for your first exam. I am a student here at UCF as well, so it is possible that there are mistakes. If you do find any, please let me know and make sure that you are checking with your professor, lecture notes, and/or textbook if you have any doubts about the information presented here. GOOD LUCK! Chapter 1 1. What does statistics deal with? a. Collection of data b. Classification of data c. Analysis of data d. Interpretation of data e. All of the above f. None of the above 2. Sampling is selecting data from some set of data whose characteristics we want to 2a. What are some examples of a sample? 3. What are the four methods of data collection? a. Surveys, observations of behavior, journal articles, US Census b. Observations of behavior, recorded information, surveys, experiments c. Experiments, journal articles, Buzzfeed survey

2 4. Match the following fundamental elements of a data set Population subset of the population Variable degree of uncertainty Sample set of all units being studied Inference Measure of reliability characteristic of an individual population unit saying something about the population based on sample 5. For the following example, determine the population, variable, sample, and inference American Females fill out a Gallup Poll that asks them if they believe they are paid less than their male peers. Gallup Poll then takes the percentage of the females that believe they are paid less than their male peers and publishes that number. Population: Variable: Sample: Inference: 6. The is the numerical summary of the population. The is the numerical summary of the sample data.

3 7. Determine whether the following data sets are qualitative or quantitative. The dogs are black, brown, white, and gray The dogs weigh 50 lb, 30 lb, and 12 lb The heights of every student in a classroom were taken to find the average height People were asked whether or not they exercised at least 3 times per week 8. What kind of sample is this: every subject has the same chance of being included. a. Simple b. Complex c. Systematic d. Simple random Chapter 2 9. Define the following: Class Class frequency

4 Class relative frequency 10. T/F: It does not matter in what order we put categories when determining frequency. 11. Using the following set of data, determine the number of classes, number of observations, class frequency, and class relative frequency. A survey was taken, asking people about the number of cars they had registered to their households. The responses are below Class Frequency Relative Frequency

5 12. A bar chart is used when the variable is a. Quantitative b. Qualitative c. Quantitative or qualitative d. None of the above 13. Determine how many classes and how many observations are in the following bar chart. Number of classes: Number of observations: a. 200 b. 50 c. 100 d. 150 What do the numbers on the y axis represent? (there s a name for this)

6 14. Draw a pie chart for the above bar chart. 15. Draw a stem and leaf display for the following test grades

7 16. Determine the number of classes, the number of observations, and the midpoints in the histogram below. Classes: Observations: Midpoints: 17. Given the set of data, find the following. Number of pets: 1, 2, 4, 2, 3, 0, 0, 5, 2, 1 x =

8 2 x = ( x ) 2 = 18. Label the following graphs as either left skewed or right skewed. Draw a line where the median is and another line where the mean could be.

9 19. How do we find the standard deviation? x2 a. n 1 ( x)2 n b. Square root of sample variance c. x x i (x i x)2 d. n 1 e. All of the above work, they are different formulas 20. Given the following information, determine how many deviations away from the mean all of the data lies. Mean = 24.7 Standard Deviation (SD): Determine which of the definitions describes chebyshev s rule and which describes the empirical rule. 68% of data fall within 1 SD of the mean 95% of data fall within 2 SD of the mean 99.7% of data fall within 3 SD of the mean Within 2 SD, you will find at least Within 3 SD, you will find at least of the data of the data

10 22. For a given set of data with a mean of $2,100 and a standard deviation of $200, what can be said about the proportion of observations that are a. Between $1,900 and $2,300 b. Between $1,700 and $2,500 c. >$2,800 d. >$2, What is the equation for z score? a. x x s x s b. x c. (x i x)

11 24. What does z score tell us? a. How many observations are within k standard deviations b. How many standard deviations away from the mean an observation is c. What percentage of observations fall k standard deviations from the mean d. None of the above 25. Given the following information, determine which test score is better. The data is mound shaped. SAT: mean = 1000, SD = 200 ACT: mean = 21, SD = 6 SAT score of 1250 or ACT score of 31

12 26. What bivariate relationships do the following graphs have between their x and y? 27. What does the correlation coefficient (r) tell us? a. The percentage of data points between a given interval b. The strength and direction of a linear relationship between two variables. c. Both a and b d. Neither a nor b

13 28. Under what circumstance do we know that correlation is significant? a. When r = critical value b. When r > critical value c. When r < critical value 29. Given the following, determine whether or not the correlation is significant. r = n = 11 α = What is the equation used to determine how y changes defined by the values of x? (in other words, how do we find the line that best fits the graph) 30a. Define each variable from the equation above.