VIEWS: 0 PAGES: 3 POSTED ON: 5/17/2013
1.A) Classify the following as an example of nominal, ordinal, interval, or ratio level of measurement, and state why it represents this level: major field of study of 100 college students (B) Determine if this data is qualitative or quantitative: Red hair (C) In your own line of work, give one example of a discrete and one example of a continuous random variable, and describe why each is continuous or discrete. 2.A large group of teenagers is divided into two smaller groups of 125 each, and each group watches a different movie. One group watches a love story while the other group watches a movie containing several scenes with violence. The teenagers are then asked questions to uncover unconscious associations and determine their level of aggression. I. What is the population? II. What is the sample? III. Is the study observational or experimental? Justify your answer. IV. What are the variables? V. For each of those variables, what level of measurement (nominal, ordinal, interval, or ratio) was used to obtain data from these variables? 3.Construct both an ungrouped and a grouped frequency distribution for the data given below: 42 46 52 50 54 51 51 49 54 42 55 49 53 50 55 41 53 52 47 45 4.Given the following frequency distribution, find the mean, variance, and standard deviation. Please show all of your work. Class Frequency 31-33 18 34-36 18 37-39 10 40-42 15 43-45 5 5.The following data lists the average monthly snowfall for January in 15 cities around the US: 43 16 38 28 7 31 18 37 35 5 43 23 24 29 22 Find the mean, variance, and standard deviation. Please show all of your work. 6.Rank the following data in increasing order and find the positions and values of both the 36th percentile and 58th percentile. Please show all of your work. 5 5 1 3 8 7 7 7 0 0 9 8 7. For the table that follows, answer the following questions: x y 1 1/2 2 1 3 3/2 4 - Would the correlation between x and y in the table above be positive or negative? - Find the missing value of y in the table. - How would the values of this table be interpreted in terms of linear regression? - If a “line of best fit” is placed among these points plotted on a coordinate system, would the slope of this line be positive or negative? 8.Determine whether each of the distributions given below represents a probability distribution. Justify your answer. (A) x 1 2 3 4 P(x) 0.25 5/12 1/3 1/6 (B) x 3 6 8 P(x) 0.1 3/5 0.3 (C) x 20 30 40 50 P(x) 0.2 - 0.7 0.3 0.2 9.A set of 50 data values has a mean of 22 and a variance of 16. I. Find the standard score (z) for a data value = 14. II. Find the probability of a data value < 14. III. Find the probability of a data value > 14. Show all work. 10.Answer the following: (A) Find the binomial probability P(x = 6), where n = 12 and p = 0.30. (B) Set up, without solving, the binomial probability P(x is at most 6) using probability notation. (C) How would you find the normal approximation to the binomial probability P(x = 6) in part A? Please show how you would calculate µ and σ in the formula for the normal approximation to the binomial, and show the final formula you would use without going through all the calculations. 11.Assume that the population of heights of male college students is approximately normally distributed with mean of 73.16 inches and standard deviation of 6.39 inches. A random sample of 70 heights is obtained. Show all work. (A) Find p(x>74.50) (B) Find the mean and standard error of the xbar distribution (C) Find p(xbar> 74.50) (D) Why is the formula required to solve (A) different than (C)? 12. Determine the critical region and critical values for z that would be used to test the null hypothesis at the given level of significance, as described in each of the following: (A) and , = 0.05 (B) and , = 0.10 (C) and, = 0.01 13.Describe what a type I and type II error would be for each of the following null hypotheses: : This is not the least expensive dishwasher. 14. A researcher claims that the average age of people who buy theatre tickets is 44. A sample of 30 is selected and their ages are recorded as shown below. The standard deviation is 7. At = 0.05 is there enough evidence to reject the researcher’s claim? Show all work. 45 38 60 45 63 37 45 43 52 48 67 38 45 44 41 45 50 45 55 39 45 46 57 41 39 41 66 39 39 55 a correct null and alternative hypothesis for testing the claim that 15. Write the mean life of a battery for a cell phone is at least 55 hours.