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25 Cards in this Set
- Front
- Back
State the 68-95-99.7 rule.
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The 68-95-99.7 rule describes what percent of observations lie within one, two ,and three standard deviations of the mean.
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What are the three assumptions for fitting a regression line?
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-assumption of linearity
-assumption of independence -assumption of constant variant |
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Name four types of graphs you might use to represent quantitative data.
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-stem and leaf plot
-dot plot -histogram -box and whisker plot |
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Define categorical data
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It describes different groups for the variable.
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Name the four properties of the normal distribution density curves.
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-follow empirical rule(68-95-99.7 rule)
-has a total area of 1.0 -be above horizontal axis -it's symmetric around the mean. |
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What do we do with suspected outliers?
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-observe
-see if it is influential -check if it is a valid part of the study. |
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Define simple random sample (SRS).
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A portion of population where every individual has an equal chance of being selected.
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What numerical measures of central tendency and dispersion best describe a symmetric distribution?
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X and S for sample and ä and ì for population.
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When we write the least squares regression line, the slope and y-intercept are found by minimizing the sum of squared distances between what two values?
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The observed and the predicted.
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What does R square measure?
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It measures the reduction of variability in the response variable.
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Define a statistic.
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It is calculated from a sample of a population and estimates a parameter.
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Define a discrete quantitative variable.
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A variable set that has gap between the values the variable may assume.
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What does the sample correlation coefficient measure?
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It measures the strenght and direction of a linear relationship denoted.
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What numerical measures of central tendency and dispersion best describe a distribution that is skewed or has outliers?
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Five number summaries.
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Define a parameter.
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It defines numerically the center and/or spread of a population's distribution.
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Define quantitative data.
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It describes a quantity or numeric value for the variable for which adding and averaging make sense.
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Define a continuous quantitative variable.
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A set of variable that does not have gaps between the values the variable may assume.
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Define bias.
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It is when one response is systematically favored over another.
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If you wanted to predict Y, for what range of X values would you feel confident using your regression equation to do so?
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The range of x of what you study.
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What do residuals measure?
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Residuals measure the difference between an observed value of the reponse and the value predicted by the regression line.
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What is the first step in fitting a linear regression equation?
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I don't know
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Name two types of graphs you might use to represent categorical data.
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-pie chart
-bar chart |
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What is the first step in data analysis?
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The first step is to make a graph.
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What is a lurking variable?
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They are variable that have an effect on the response but have not been measured.
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Define population.
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Entire collection of individual of interest.
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