ENR 2000 Exam 1_ Review 2024.pdf

ENR 2000 Exam #1 Review Problems 1. Develop a formal grouped frequency distribution for the following values (visits to a state park over a two-month period). Use i=3, and be sure to include the midpoint for...

ENR 2000 Exam #1 Review Problems 1. Develop a formal grouped frequency distribution for the following values (visits to a state park over a two-month period). Use i=3, and be sure to include the midpoint for each group. 15 2 14 5 13 8 6 2 1 12 9 4 10 6 1 7 10 8 3 6 11 4 15 11 12 9 1 10 2. What is the mean, median, and mode for this set of values? 3. Compute the range and interquartile range for this set of values. 4. Are there any outliers? 5. Draw a box and whiskers plot for this data. 6. Draw a stem and leaf diagram for this data. 7. Indicate if the following are nominal, ordinal, interval, or ratio data: a. Three main types of birds found in Central Ohio b. The top three winners in a marathon c. Temperature readings over the past three days d. The height of three trees located next to Kottman Hall e. Highways 70, 71, 270 and 670 8. For which of the above (a-e) is it appropriate to compute a mean? 1 9. What does it mean if the distribution of data is skewed? 10. Which of the following is an open-ended class interval? a. 10-15 b. Less than 5 c. 100 - 1000 d. 2 11. Compute the mean for the following data: Semester GPA Credit Hours 4.00 20 2.00 6 3.85 15 12. You received word that your essay for a college scholarship was ranked in the 10th percentile. Should you be excited about this news? 13. What is the difference between σ and S? 14. What is the difference between µ and 𝑋𝑋 ? 15. What is a deviation score? 16. For the following values, please compute the standard deviation. Compute using the deviation- score formula or the raw score formula. Boxes of Girl Scout Cookies Sold 4 2 10 6 0 2 17. Convert each of the above values to standard deviation units (z scores). 18. What is the mean and standard deviation of the z scores? 19. If you obtain a z score of 3.5, how would you describe this value: 2  a. Close to the mean b. Far away from the mean c. Below the mean d. The mean score 20. You observe the number of minutes it takes for a group of high school students to complete a hike. The mean for the group was 48 and median was 60. Is this data positively or negatively skewed? How do you know? 21. Assuming the mean of Group 1 is 25, the mean of Group 2 is 35, and σ for the groups is 8, is the effect size, small, medium, or large? 22. What does effect size mean? 23. You learn that the correlation between time to complete a hike and hours of sleep obtained the night before the hike is -0.85. How would you describe this correlation? _______________ (weak, moderate, strong) ________________ (positive, negative) 24. How would you interpret this? a. The more sleep you obtained, the longer it takes to complete the hike b. The more sleep you obtained, the less time it takes to complete the hike c. There is almost no relationship between time to complete the hike and sleep. 25. You also learn that the correlation between time to the complete a hike and age is 0.45. How would you describe this correlation? _______________ (weak, moderate, strong) ________________ (positive, negative) a. The older a person is, the longer it takes to complete the hike b. The younger a person is, the more time it takes to complete the hike c. There is almost no relationship between time to complete the hike and age. 26. What are the 3 formulas for computing r, the correlation coefficient? What information do you need for each formula? 27. The equation for predicting a value of 𝑌𝑌 is 𝑌𝑌 = a + bX, where a is the y intercept and b is the slope of the line. Assume the formula, 𝑌𝑌 = 4.00 + 5X. For each unit change in X, how much will the value of Y change? 3 28. The correlation between automobiles on the street (X) and cyclists on the sidewalk (Y) is 0.42. Assume values of 𝑋𝑋 = 80, Sx = 12 and 𝑌𝑌 = 14, Sy = 3. If you observe 50 autos on the street, what is your predicted value of cyclists? 29. What does Σ mean? 30. Compute the correlation between X (positive mood) and Y (amount of sunshine). Use any of the three formulas. Mood score (X) Hours of Sunshine (Y) 10 12 7 9 2 4 4 10 31. What is the coefficient of determination for the above data? 32. Data from the human resources office at a large research university show that the hourly wages paid to library assistants reflect a normal distribution with a mean of $12.00 per hour and a standard deviation of $2.50. Determine: a. The probability of selecting at random from personnel files a library assistant who earns an hourly wage of $15 or more. b. The probability of selecting at random from the personnel files a library assistant who earns an hourly wage of $11.00 or less. 33. You play a board game with friends and score a total of 200 points. The mean score was 180 points with a standard deviation of 10. You play a computer game and score 110 points. The mean score for this game was 82 points with a standard deviation of 25. Which type of game did you receive the relatively higher score? 34. Assume a normal distribution. What would be the probabilities of the following z scores: a. Less than -0.80 b. Between the mean and 1.35 c. Between -2.5 and -2.0 d. Greater than 1.7 4 35. Estimate the dissolved oxygen concentration from a lake sample with a signal intensity of 0.153. Use the equation of the straight line from the following scatterplot. Calibration Curve of dissolved oxygen 0.8 0.7 y = 0.03x + 0.0296 R² = 0.9951 Signal Intensity, a.u. 0.6 0.5 0.4 0.3 0.2 0.1 0 0 5 10 15 20 25 30 O2 concentration, mg/L 5