Practice Test 1 http://staging2.cnx.org/content new Practice Test 1 **new** 2013/10/18 02:18:58.419 GMT-5 2013/10/18 02:18:58.487 GMT-5 Words Numbers Words Numbers techsupport@cnx.org words_stats words_stats words_stats Mathematics and Statistics en
1.1: Definitions of Statistics, Probability, and Key Terms Use the following information to answer the next three exercises. A grocery store is interested in how much money, on average, their customers spend each visit in the produce department. Using their store records, they draw a sample of 1,000 visits and calculate each customer’s average spending on produce. Identify the population, sample, parameter, statistic, variable, and data for this example. population sample parameter statistic variable data population: all the shopping visits by all the store’s customers sample: the 1,000 visits drawn for the study parameter: the average expenditure on produce per visit by all the store’s customers statistic: the average expenditure on produce per visit by the sample of 1,000 variable: the expenditure on produce for each visit data: the dollar amounts spent on produce; for instance, \$15.40, \$11.53, etc What kind of data is “amount of money spent on produce per visit”? qualitative quantitative-continuous quantitative-discrete c The study finds that the mean amount spent on produce per visit by the customers in the sample is \$12.84. This is an example of a: population sample parameter statistic variable d Use the following information to answer the next two exercises. A health club is interested in knowing how many times a typical member uses the club in a week. They decide to ask every tenth customer on a specified day to complete a short survey including information about how many times they have visited the club in the past week.
1.3: Frequency, Frequency Tables, and Levels of Measurement Compute the mean of the following numbers, and report your answer using one more decimal place than is present in the original data: 14, 5, 18, 23, 6 13.2
2.1: Stem-and Leaf Graphs (Stemplots), Line Graphs, and Bar Graphs Use the following information to answer the next four exercises. The midterm grades on a chemistry exam, graded on a scale of 0 to 100, were: 62, 64, 65, 65, 68, 70, 72, 72, 74, 75, 75, 75, 76,78, 78, 81, 83, 83, 84, 85, 87, 88, 92, 95, 98, 98, 100, 100, 740 Do you see any outliers in this data? If so, how would you address the situation? The value 740 is an outlier, because the exams were graded on a scale of 0 to 100, and 740 is far outside that range. It may be a data entry error, with the actual score being 74, so the professor should check that exam again to see what the actual score was. Construct a stem plot for this data, using only the values in the range 0–100.
Stem Leaf 6 2 4 5 5 8 7 0 2 2 4 5 5 5 6 8 8 8 1 3 3 4 5 7 8 9 2 5 8 8 10 0 0
Describe the distribution of exam scores. Most scores on this exam were in the range of 70–89, with a few scoring in the 60–69 range, and a few in the 90–100 range.
2.2: Histograms, Frequency Polygons, and Time Series Graphs In a class of 35 students, seven students received scores in the 70–79 range. What is the relative frequency of scores in this range? RF= 7 35 =0.2 Use the following information to answer the next three exercises. You conduct a poll of 30 students to see how many classes they are taking this term. Your results are: 1; 1; 1; 1 2; 2; 2; 2; 2 3; 3; 3; 3; 3; 3; 3; 3 4; 4; 4; 4; 4; 4; 4; 4; 4 5; 5; 5; 5 You decide to construct a histogram of this data. What will be the range of your first bar, and what will be the central point? The range will be 0.5–1.5, and the central point will be 1. What will be the widths and central points of the other bars? Range 1.5–2.5, central point 2; range 2.5–3.5, central point 3; range 3.5–4.5, central point 4; range 4.5–5.5., central point 5. Which bar in this histogram will be the tallest, and what will be its height? The bar from 3.5 to 4.5, with a central point of 4, will be tallest; its height will be nine, because there are nine students taking four courses. You get data from the U.S. Census Bureau on the median household income for your city, and decide to display it graphically. Which is the better choice for this data, a bar graph or a histogram? The histogram is a better choice, because income is a continuous variable. You collect data on the color of cars driven by students in your statistics class, and want to display this information graphically. Which is the better choice for this data, a bar graph or a histogram? A bar graph is the better choice, because this data is categorical rather than continuous.
2.4: Box Plots Use the following information to answer the next three exercises. 1; 1; 2; 3; 4; 4; 5; 5; 6; 7; 7; 8; 9 What is the median for this data? 5 What is the first quartile for this data? 3 What is the third quartile for this data? 7 Use the following information to answer the next four exercises. This box plot represents scores on the final exam for a physics class. What is the median for this data, and how do you know? The median is 86, as represented by the vertical line in the box. What are the first and third quartiles for this data, and how do you know? The first quartile is 80, and the third quartile is 92, as represented by the left and right boundaries of the box. What is the interquartile range for this data? IQR = 92 – 80 = 12 What is the range for this data? Range = 100 – 75 = 25