Question 21 A measure of the average value of a random variable is called a(n) Answer variance standard deviation expected value None of the answers is correct. Question 22 After the data has been arranged from smallest value to largest value, the value in the middle is called the Answer range median mean None of the other answers are correct. Question 23 Exhibit 2-1 The numbers of hours worked (per week) by 400 statistics students are shown below. Number of hours Frequency 0 – 9 20 10 – 19 80 20 – 29 200 30 – 39 100 Refer to Exhibit 2-1. The number of students working 19 hours or less Answer is 80 is 100 is 180 is 300 Question 24 When the data have the properties of ordinal data and the interval between observations is expressed in terms of a fixed unit of measure, the variable has which scale of measurement? Answer nominal ordinal interval ratio Question 25 Exhibit 2-1 The numbers of hours worked (per week) by 400 statistics students are shown below. Number of hours Frequency 0 – 9 20 10 – 19 80 20 – 29 200 30 – 39 100 Refer to Exhibit 2-1. The percentage of students working 10 – 19 hours is Answer 20% 25% 75% 80% Question 26 A researcher is gathering data from four geographical areas designated: South = 1; North = 2; East = 3; West = 4. The designated geographical regions represent Answer categorical data quantitative data directional data either quantitative or categorical data Question 27 In hypothesis testing, the critical value is Answer a number that establishes the boundary of the rejection region the probability of a Type I error the probability of a Type II error the same as the p-value Question 28 A regression analysis between sales (in $1000) and price (in dollars) resulted in the following equation = 50,000 – 8x The above equation implies that an Answer increase of $1 in price is associated with a decrease of $8 in sales increase of $8 in price is associated with an increase of $8,000 in sales increase of $1 in price is associated with a decrease of $42,000 in sales increase of $1 in price is associated with a decrease of $8000 in sales Question 29 The standard deviation is the Answer variance squared square root of the sum of the deviations from the mean same as the expected value positive square root of the variance Question 30 From a population of 200 elements, the standard deviation is known to be 14. A sample of 49 elements is selected. It is determined that the sample mean is 56. The standard error of the mean is Answer 3 2 greater than 2 less than 2 Question 31 For any continuous random variable, the probability that the random variable takes on exactly a specific value is Answer 1.00 0.50 any value between 0 to 1 zero Question 32 The control limits for an np chart are how many standard deviations above and below the expected number of defectives? Answer one two three four