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21 Cards in this Set
- Front
- Back
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As part of a class project, a college student wanted to estimate the proportion of students at his college that owned a red car. To estimate this proportion he went to a large student parking lot during the middle of a class day. He found that 325 out of 1037 cars (31%) were red. This sample is best described as a ________________________.
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convenience sample
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A political scientist wants to know how college students feel about the social security system. She obtains a list of the 3140 undergraduates at her college and mails a questionnaire to 300 students selected at random. Only 108 of the questionnaires are returned. This sample is best described as a _______________________.
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volunteer response sample (double check to make sure this is correct, its from WA #2
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______________controls for effect of lurking variables?
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randomization
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Based on a sampling distribution, we can construct ____________ or do __________ for the parameter
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Confidence Interval or do Hypothesis Testing
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When we look at a statistic from a simple random sample, we find that statistic has a predictable pattern called the ________________.
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sampling distribution
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what happens if the sample size increases?
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true mean (population proportion) of the sampling distribution will not change, standard deviation will decrease (miranda's notes page 5)
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what are the properties of a normal distribution?
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- symmetric
-bell shaped - center determined by mean -spread determined by standard deviation |
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For any bell shaped curve approximately __% of the values fall within 1 standard deviation of the mean in either direction
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68%
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For any bell shaped curve approximately __% of the values fall within 2 standard deviation of the mean in either direction
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95%
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For any bell shaped curve approximately __% of the values fall within 3 standard deviation of the mean in either direction
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99.7%
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There are 3 rows of seats in a class room, 10 seats in each row. I want to know if the students can see the blackboard clearly. I select the 10th, 20th, and 30th students. What type of sampling procedure is this?
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Systematic Sample (select every k-th individual from the sampling frame)
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What is the difference between a histogram and a bar graph?
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In a bar graph each bar represents how many items are in a category, in a histogram each bar represents how man items are in a range of values
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In a pie chart, each slice of the pie corresponds to a specific ___________. Pie charts are used to make graphs of ___________ variables.
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In a pie chart, each slice of the pie corresponds to a specific CATEGORY. Pie charts are used to make graphs of CATEGORICAL VARIABLES
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In a pie chart, each slice of the pie corresponds to a specific ___________. Pie charts are used to make graphs of ___________ variables.
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In a pie chart, each slice of the pie corresponds to a specific CATEGORY. Pie charts are used to make graphs of CATEGORICAL VARIABLES
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Any data that exists outside the region of [ Q1 - (1.5x IQR) ] to [ Q3+(1.5*IQR) ] is ____________________.
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an outlier!
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What is the difference between a stem and leaf plot and a histogram?
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Every individual data value is shown in a stem-and-leaf plot but NOT every data value is shown in a histogram
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The mean is sensitive to _____________________, the median is not!
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outliers
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Outliers with large values __________the mean, while outliers with small values ____________ the mean.
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Outliers with large values increase the mean, while outliers with small values decrease the mean.
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what is the purpose of knowing the range?
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how spread out the extreme values are
(the distance between the max and min values) |
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A ______________ is always symmetric.
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A normal distribution is always symmetric.
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The standard normal distribution is always centered at _______.
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The standard normal distribution is always centered at zero.
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