Statistics Chapter 2 Homework Flashcards
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Questions and Answers

For the following frequency distribution of exam scores, how many students had scores lower than X = 80?

  • 2
  • 3 (correct)
  • 7
  • 8

    • For the following distribution, how many people had scores less than X = 20?

  • 5
  • 11
  • 12
  • 10 (correct)

    • For the following distribution, how many people had scores greater than X = 14?

  • 5
  • 7 (correct)
  • 11
  • 10

    • For the following distribution, what is the width of each class interval?

    <p>5</p> Signup and view all the answers

    What kind of frequency distribution graph shows the frequencies as bars, with no space between adjacent bars?

    <p>a histogram</p> Signup and view all the answers

    What kind of frequency distribution graph shows the frequencies as bars that are separated by spaces?

    <p>a bar graph</p> Signup and view all the answers

    What term is used to describe the shape of a distribution in which the scores pile up on the left-hand side of the graph and taper off to the right?

    <p>positively skewed</p> Signup and view all the answers

    For the scores shown in the accompanying stem and leaf display, what is the highest score in the distribution?

    <p>84</p> Signup and view all the answers

    If the following scores were placed in a stem and leaf display, how many leaves would be associated with a stem of 6?

    <p>3</p> Signup and view all the answers

    It is customary to list the score categories in a frequency distribution from the highest down to the lowest.

    <p>True</p> Signup and view all the answers

    A grouped frequency distribution table lists one interval as, 20-29. The width of this interval is 9 points.

    <p>False</p> Signup and view all the answers

    Construct a frequency distribution for the blood types for 40 people.

    <p>O: 19, A: 13, B: 5, AB: 3</p> Signup and view all the answers

    Find the value of the missing entry in the relative frequency table.

    <p>0.4</p> Signup and view all the answers

    If a histogram has a bar that is taller than the others, then:

    <p>the bar corresponds to the class interval containing the most observations.</p> Signup and view all the answers

    Identify the overall shape of the distribution from the given stem and leaf plot.

    <p>bell-shaped</p> Signup and view all the answers

    Which of the following is a technique for improving a stemplot with very few stems but many leaves?

    <p>splitting stems.</p> Signup and view all the answers

    What is the difference between a bar chart and a histogram?

    <p>The bars on a bar chart do not touch while the bars of a histogram do touch.</p> Signup and view all the answers

    The class width is the difference between:

    <p>the upper class limit and the lower class limit of a class</p> Signup and view all the answers

    Find (a) the number of classes and (b) the class width for community hospital admissions.

    <p>4, 100</p> Signup and view all the answers

    Find (a) the number of classes and (b) the class width for live multiple births.

    <p>6, 5</p> Signup and view all the answers

    A ____________________ is a bar graph whose bars are drawn in decreasing order of frequency or relative frequency.

    <p>Pareto chart</p> Signup and view all the answers

    Determine the original set of data from the given stem and leaf plot.

    <p>56, 45, 78, 98, 64, 56, 79, 80, 97, 47, 59, 86, 67, 52, 41, 70, 82, 52, 40, 64, 61, 80</p> Signup and view all the answers

    Compute the relative frequency for the back, elbow, and knee categories respectively.

    <p>0.4, 0.0333, 0.1667</p> Signup and view all the answers

    When a data set is skewed left the mean is substantially smaller than median.

    <p>True</p> Signup and view all the answers

    When a data set is symmetric the mean is roughly equal to the median.

    <p>True</p> Signup and view all the answers

    When a data set is skewed right the mean is substantially larger than the median.

    <p>True</p> Signup and view all the answers

    When a data set is symmetric the mean is substantially larger than the median.

    <p>False</p> Signup and view all the answers

    Study Notes

    Frequency Distributions

    • To find the number of students with scores lower than a specific value, sum frequencies of intervals below that value.
    • For X = 80 in exam scores: Students scoring below 80 equals the sum of intervals 75-79 (2) and 70-74 (1), totaling 3.
    • For X = 20 in another distribution, count intervals below 20, which includes the scores 15-19 (5) and 10-14 (4), leading to 10 total.

    Class Intervals

    • Class interval width calculated as the difference between the upper and lower limits of a class.
    • For the interval 20-25, the width is 5.
    • Correct class width is crucial for creating accurate frequency distributions.

    Graphical Representations

    • A histogram displays frequencies as contiguous bars; there is no space between bars.
    • A bar graph shows frequencies as separate bars with spaces in between.
    • The shape of distribution can be skewed positively (tail on right) or negatively (tail on left).
    • A bell-shaped distribution indicates a normal distribution in data.

    Stem and Leaf Displays

    • The highest score in a stem and leaf display can be identified by finding the largest leaf.
    • Count leaves associated with each stem to understand data distribution—stem 6 corresponds to three leaves (62, 64, 66).

    Frequency Distribution Characteristics

    • It is customary for frequency distributions to be organized from highest to lowest.
    • A grouped frequency distribution class width must be calculated accurately to reflect intervals.

    Statistical Terminology

    • A Pareto chart displays bars in descending order of frequency, aiding in identifying the most significant categories.
    • Relative frequency conveys the proportion of each category in comparison to the total.

    Data Distribution Analysis

    • Left skewed data means mean < median, while right skewed means mean > median.
    • Symmetric distributions have closely aligned mean and median values.
    • When analyzed, they help understand trends and deviations in data sets.

    Classifications and Averages

    • A distribution's classification can involve identifying the number of classes and their widths using specific criteria.
    • Multiple births data reflects the complexity of statistics through intervals and frequency counts.

    Practice Scenarios

    • Engaging in exercises to determine class intervals, both through calculations of widths and identification of frequencies, enhances statistical competency.
    • Regularly correct affirmations regarding relationships between means and medians across varying distributions solidifies foundational knowledge.

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    Description

    Test your knowledge of frequency distributions with these flashcards focused on Chapter 2 of your statistics course. Each card presents a different scenario where you calculate the number of students or individuals below a specific score. Perfect for mastering key concepts in statistics!

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