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    Know Your Statistical Concepts

    Each question is a choice-summary multiple choice question that presents you with a statistical concept and then 4 numbered statements. You must decide which (if any) of the numbered statements is/are true as they relate to the statistical concept.


    When you collect data you have several different Measures of Center that are available to you when you want to describe your data. These include:
    I. The Median Value.
    II The Mode.
    III. The Mean Value.
    IV. The Standard Deviation.


    The traditional 5-number summary of a data set includes:
    I. The Mean Value.
    II. The Minimum and Maximum Values in the data set.
    III. The Range.
    IV. The Quartiles.


    The characteristics of a Binomial Random Variable include:
    I. There are only two outcomes possible for each trial; a Success or a Failure.
    II. The probability of a success stays constant over all trials.
    III. A fixed number of trials is conducted.
    IV. The possible values of a binomial random variable are: 0, 1, 2, 3, ..., n.


    Which of the following are true about the Median Value?
    I. The median is the second quartile.
    II. The median tends to be insensitive to the presence of outliers in a data set.
    III. The median is one way to measure the center of a data set.
    IV. The median divides a data set "in half"; 50% of the values will be less than or equal to the median and 50% of the values will be greater than or equal to the median.


    When you perform a hypothesis test:
    I. If the p-value is less than the level of significance then you should reject the null hypothesis.
    II. You choose the p-value, which is the probability that you make a Type I Error.
    III. A Type II Error is said to occur whenever the null hypothesis is actually false, but your data leads you to fail to reject the null hypothesis.
    IV. Large p-values tend to support the alternative hypothesis.


    Which of the following statements is/are true about outliers in a data set?
    I. The mean value of data set tends to be unaffected by the presence of outliers.
    II. Data sets that contain outliers are generally preferred over data sets that do not contain outliers.
    III. The interquartile range of a data set tends to change significantly when outliers are included in the data set.
    IV. Outliers in a data set are extreme values in comparison to the other values in the data set; either extremely large, or extremely small in comparison.


    In a Simple Linear Regression, the value of R-Squared:
    I. Is known as the Correlation Coefficient.
    II. Tells you the percentage of variation in the dependent variable that can be explained by the regression model.
    III. Will allow you to tell if the two variables are negatively or positively linearly related.
    IV. Cannot be negative and cannot be bigger than 1.


    When you collect data you have several different Measures of Variation that are available to you when you want to describe your data. These include:
    I. The Range.
    II. The Interquartile Range.
    III. The Standard Deviation.
    IV. The Confidence Interval.


    Which of the following types of Measurement Scales have a natural and meaningful sense of order to the values on the scale and have a true 0 on them (that is, a value of 0 actually means that there is absolutely none of what is being measured)?
    I. A Nominal Scale.
    II. An Ordinal Scale.
    III. An Interval Scale.
    IV. A Ratio Scale.


    The characteristics of EVERY normally distributed random variable include:
    I. The distribution is centered at the population mean value.
    II. The spread of the distribution is determined by the population variance.
    III. The distribution is symmetric and bell-shaped.
    IV. Normally distributed random variables can never take negative values.