Web Calculator Exercise 2
Question 1 a. Mean age = 960/20=48 b. Standard Deviation = 10. 74832 Web address: http://easycalculation. com/statistics/standard-deviation. php Frequency distribution table for denomination. Score f(frequency) 1 1 2 2 4 2 5 1 6 3 7 3 8 1 9 3 10 3 12 1 N=30 c. What is the percentage of people who identify themselves as Baptist? 3/20 = . 15 x 100 = 15% What is the mode of church attendance? 5 Question 2 a. What is the Z score for a car with a price of $33,000? Z=2. 85714286 b. What is the Z score for a car with a price of $30,000? Z=2 Web address for calculator: http://www. danielsoper. com/statcalc3/calc. spx? id=22 c. At what percentile rank is a car that sold for $30,000? 97. 72% Web calculator used: http://easycalculation. com/statistics/zscore-to-percentile. php 3. One student’s Math score was 70 and the same individual’s English score was 84. On which exam did the student do better? Math: +3 points divided by 9. 58 SD = . 3132 English: + 6 points divided by 12. 45 SD = . 482 The student did better on the English test. 4. Suppose you administered an anxiety test to a large sample of people and obtained normally distributed scores with a mean of 45 and standard deviation of 4. Do not use web-calculator to answer the following questions.
Instead, you need to use the Z distribution table in Appendix A in Jackson’s book. a. If Andrew scored 45 on this test. What is the Z score? Z=45-45 z=0 4 b. If Anna scored 30 oh this test. What is her Z score? Z=30-45 Z=-3. 75 4 c. If Bill’s Z score was 1. 5, what is his real score on this test? 1. 5 = x-45 X=51 4 d. There are 200 students in a sample. How many of these students will have scores that fall under the score of 41? Z=41-45 Z= -1 According to Appendix A . 159 x 200 Answer = 31. 8 fall under 41 4 5. Obtain the Persaon’s r and coefficient of determination for the following relationships. . Between the IQ and psychology scores. r=. 59231 Determination= . 35084 WEB: http://easycalculation. com/statistics/r-squared. php b. Between the IQ and statistics score. r= . 73667 Determination= . 54268 WEB: http://easycalculation. com/statistics/r-squared. php c. Between the psychology scores and statistics scores. r= . 71050 Determination = . 50480 WEB: http://easycalculation. com/statistics/r-squared. php 6. Using a web-calculator, obtain the appropriate correlation coefficients. r= . 85190 http://easycalculation. com/statistics/r-squared. php