# Social Statistics #1

–/2 pointsPriviteraStats2 1.E.005.

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In an experiment, researchers measure two types of variables: independent and dependent variables.

(a) Which variable is manipulated to create the groups?

independent variabledependent variable

(b) Which variable is measured in each group?

independent variabledependent variable

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2.–/2 pointsPriviteraStats2 1.E.009.

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A quantitative variable varies by —Select— class experiment amount assignment ; a qualitative variable varies by —Select— experiment assignment class amount .

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3.–/3 pointsPriviteraStats2 1.E.011.

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State whether each of the following words best describes descriptive statistics or inferential statistics.

(a) describe

descriptive statisticsinferential statistics

(b) infer

descriptive statisticsinferential statistics

(c) summarize

descriptive statisticsinferential statistics

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4.–/2 pointsPriviteraStats2 1.E.019.

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To determine whether a new sleeping pill was effective, adult insomniacs received a pill (either real or fake), and their sleeping times were subsequently measured (in minutes) during an overnight observation period.

(a) Identify the independent variable in this study.

time spent sleepingnumber of insomniacs sleeping pill (real or fake)number of observation periods

(b) Identify the dependent variable in this study.

time spent sleepingnumber of insomniacs sleeping pill (real or fake)number of observation periods

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5.–/3 pointsPriviteraStats2 1.E.021.

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Researchers are interested in studying whether personality is related to the month in which someone was born.

(a) What scale of measurement is the month of birth?

intervalnominal ratioordinal

(b) Is it appropriate to code the data? Explain.

—Select— Yes, it is appropriate No, it is not appropriate to numerically code “months” because it is —Select— an interval an ordinal a nominal a ratio scale variable.

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6.–/4 pointsPriviteraStats2 1.E.025.

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State whether each of the following are continuous or discrete data.

(a) time in seconds to memorize a list of words

continuousdiscrete

(b) number of students in a statistics class

continuousdiscrete

(c) the weight in pounds of newborn infants

continuousdiscrete

(d) the SAT score among college students

continuousdiscrete

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7.–/1 pointsPriviteraStats2 1.E.031.

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Szklarska, Koziel, Bielicki, and Malina (2007) hypothesized that taller young men are more likely to move up the scale of educational attainment compared with shorter individuals from the same social background. They recruited 91,373 nineteen-year-old men to participate in the study. Do these participants most likely represent a sample or population? Explain.

The 91,373 nineteen-year-old-men likely represent a population of men of all ages.The 91,373 nineteen-year-old-men likely represent a sample of men of all ages in a much larger population. The 91,373 nineteen-year-old-men likely represent a population of 19-year-old men.The 91,373 nineteen-year-old-men likely represent a sample of all 19-year-old men in a much larger population.

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8.–/1 pointsPriviteraStats2 2.E.005.

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Researchers often prefer to report cumulative percents from the bottom up to explain how certain scores rank at or below other scores in a distribution. What is this type of summary called?

a distribution summaryan open interval a cumulative frequencya percentile ranka lower boundary

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9.–/5 pointsPriviteraStats2 2.E.011.

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Below is the number of hand-washing episodes 20 patients with obsessive-compulsive disorder reported having the previous day.

9, 11, 22, 3, 7, 13, 14, 9, 5, 21,18, 10, 19, 10, 6, 12, 8, 16, 9, 17

(a) Create a simple frequency distribution for these grouped data with four intervals.

IntervalFrequency18-2213-178-123-7(b) Which interval had the largest frequency?

Interval: 18-22Interval: 13-17 Interval: 8-12Interval: 3-7

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10.–/4 pointsPriviteraStats2 2.E.015.

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The upper boundaries for a distribution of waiting times (in seconds) in a grocery store aisle are 48, 60, 72, and 84. List the value for each lower boundary in this distribution.

LowerboundaryUpperboundary84726048

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11.–/6 pointsPriviteraStats2 2.E.019.

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A researcher records the number of dreams that 50 college freshman students recalled during the night prior to a final exam.

Number ofDreamsCumulativeFrequency45034523012107

(a) Convert this table to a percentile rank distribution.

Number ofDreamsCumulativeFrequencyPercentileRank450 %345 %230 %121 %07 %(b) What is the number of dreams at the 60th percentile? dreams

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12.–/5 pointsPriviteraStats2 2.E.021.

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Organize the following data into a stem-and-leaf display where the following is true. (Enter numbers from smallest to largest separated by spaces. Enter NONE for stems with no values.)

154, 123, 237, 154, 127, 233, 230, 233, 238, 150232, 159, 123, 159, 239, 158, 122, 125, 156, 128

(a) the leaf has one digit

StemLeaf121523(b) the stem has one digitStemLeaf12

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13.–/3 pointsPriviteraStats2 2.E.025.

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The following is an incomplete simple frequency distribution table for the number of mistakes made during a series of military combat readiness training exercises.

Number ofMistakesFrequency10–

**A**2

**B**–940–4

**C** N = 18Find the missing values for A, B, and C.A =B =C =

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14.–/3 pointsPriviteraStats2 2.E.027.

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The following bar graph summarizes the number of nights per week a sample of college students spent studying.

(a) How many students were observed in this study? students(b) How many students studied 3 nights per week? students(c) How many students studied at least 3 nights per week? students

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15.–/2 pointsPriviteraStats2 2.E.033.

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Keith Rollag (2007) noticed that coworkers evaluate and treat “new” employees differently from other staff members. He was interested in how long a new employee is considered “new” in an organization. He surveyed four organizations ranging in size from 34 to 89 employees. He found that the “new” employee status was mostly reserved for the 30% of employees in the organization with the lowest tenure.

(a) In this study, what was the real range of employees hired by each organization surveyed? employees(b) What was the cumulative percent of “new” employees with the lowest tenure? %

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16.–/2 pointsPriviteraStats2 2.E.037.

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In February 2009, the Harris Poll asked a sample of Americans whether they thought churches and religious groups have too much or too little power and influence on Washington†. The opinions of Americans were 34% too much, 57% too little, 4% just right, and 5% unsure.

(a) What type of distribution is this?

relative percent distributioncumulative frequency distribution cumulative percent distributionsimple frequency distribution

(b) Knowing that 1,010 adults were polled nationwide, how many Americans polled felt that churches and religious groups have too little power and influence on Washington? (Round your answer to the nearest whole number.) Americans

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