DSST Statistics Practice Exam

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• Using the IQR method, an outlier is defined as...
• In hypothesis testing, the null hypothesis typically states that there is no effect or no difference.
• The statistic used to assess the strength and direction of a linear relationship between two quantitative variables, ranging from -1 to +1, is the:
• Which measure is used to summarize central tendency that is the arithmetic average?
• Which type of hypothesis test is used when the alternative hypothesis is stated as not equal to the null value (in either direction)?
• Which principle states that as the number of trials grows, empirical probabilities converge to classical probabilities?
• Who is associated with using known probabilities of the past to predict the future?
• What does R-squared tell you?
• Which statement about confidence intervals for a proportion is true?
• How is the Pearson correlation coefficient interpreted?
• State the Central Limit Theorem in brief.
• Posterior probabilities are defined as the probability of an event after observing data.
• Which statement best distinguishes stratified sampling from cluster sampling?
• Which term refers to the number of values free to vary given information such as the sample mean?
• Common sampling biases?
• Is a distribution for the number of successes in a fixed number of Bernoulli trials.
• Which sampling method involves selecting entire groups, or clusters, and including all members from the chosen clusters?
• If the correlation coefficient between X and Y is 0, what does that indicate?
• Which term is a range of values used to estimate a population parameter and is associated with a specific confidence level?
• Which measure of central tendency is most appropriate when data are skewed by extreme values?
• What characterizes stratified sampling?
• Probabilities derived only from information currently available before new data are called which?
• Recall bias occurs when respondents misremember past events. Which option describes this bias?
• Which type of data uses descriptive terms to measure or classify something of interest?
• When is a t-test used?
• States that when an experiment is conducted a large number of times, the empirical probabilities of the process will converge to the classical probabilities.
• In hypothesis testing, what does the null hypothesis typically represent?
• Which statement best describes descriptive statistics?
• Probability of a single event.
• In a one-sample t-test, which distribution is used to determine critical values?
• Which term represents the probability of making a Type I error?
• Which statement describes the effect of increasing sample size on the confidence interval for a proportion?
• In a one-sided test, if p < α, what does this indicate?
• Which term describes the probability that a constructed confidence interval will contain the true population parameter?
• Which statistic is calculated by adding all values and dividing by the number of observations?
• Which statistic is the standard deviation of the sampling distribution of the sample proportion?
• When is a nonparametric test preferred over a parametric test?
• What is homoscedasticity?
• In cluster sampling, what is typically done?
• Who merged science and statistics and promoted the use of statistics in driving a process?
• A random variable is ____ if it can assume any numerical value within an interval as a result of measuring the outcome of an experiment.
• The probability of at least one of A or B occurs is denoted by which expression?
• Which term describes events that cannot occur at the same time?
• Which statement about nominal data is true?
• Chebyshev's Theorem applies to any distribution and the Empirical Rule applies only to bell-shaped distributions. Which statement is true?
• Fundamental counting principle: If one event can occur in m ways and a second in n ways, the total number of ways both events can occur is:
• How does increasing sample size affect the standard error?
• Nominal level of measurement is best described as:
• What is the key concept in statistics that involves drawing a conclusion from available evidence?
• In hypothesis testing, which statement best describes the null hypothesis?
• Which statement about the median is true?
• What does a p-value represent?
• Pearson's correlation coefficient, r, is a measure of the linear relationship between two variables X and Y, with r ranging from:
• Which level of measurement involves the ability to rank or order values from highest to lowest but does not permit meaningful differences between categories?
• If ANOVA is significant, which statement is an accurate interpretation?
• Why is the IQR robust to outliers?
• Has the following characteristics: (1) the experiment consists of counting the number of occurrences of an event over a period of time, area, distance, or any other type of measurement; (2) the mean of the Poisson distribution has to be the same for each interval of measurement; (3) the number of occurrences during one interval is independent of the number of occurrences in any other interval.
• Which option lists two nonparametric tests for comparing two independent samples?
• Which distribution displays all possible sample means along with their probabilities for a given sampling process?
• In a chi-square goodness-of-fit test, what is typically compared to assess fit?
• Which expression represents the number of distinct arrangements of n distinct objects (permutations)?
• How do you perform a one-sample t-test?
• Which error occurs when you reject the null hypothesis even though it is true?
• What describes how far individual data values deviate from the mean?
• Which data scale is characterized by a true zero and permits multiplication and division operations?
• What does the chi-square test for independence assess?
• Which data level allows ranking but does not imply equal intervals between categories?
• Is the mean of a probability distribution
• Provides a range of values that best describes the population?
• What is the meaning of adjusted R-squared?
• In a one-way ANOVA, the F-statistic compares which variances?
• Which statement about p-values is correct?
• What is an independent two-sample t-test?
• What characterizes simple random sampling?
• Which term is a single value that best describes the population of interest, with the sample mean being the most common?
• Which term is a range of values used to estimate a population parameter and is associated with a specific confidence level?
• The value that splits a data set into two halves is called the
• What is the mean of a dataset?
• What does the slope represent in simple linear regression y = β0 + β1 x?
• Three independent choices with m, n, p options respectively: total outcomes?
• If two events are independent, P(A and B) equals which expression?
• What is the purpose of a confidence interval for a proportion?
• In a Binomial(n, p), what does the variance depend on?
• Indicates the number of observations that are classified according to two variables. The intersection of Events A and B represents the number of instances where Events A and B occur at the same time.
• When is a z-test appropriate for testing a population mean?
• The complete absence of the object being measured is indicated by what feature of a measurement scale?
• The probability that both events A and B occur is denoted by which expression?
• The standard deviation is the square root of which measure?
• Which sampling method divides the population into mutually exclusive groups called strata and randomly samples from each group?
• What is a z-score and how is it computed?
• The probability of committing a Type II error is commonly denoted by which symbol?
• Which statistic is considered resistant to outliers?
• Number of ways to choose 3 from 10 when order does not matter?
• Name a key assumption of linear regression.
• For mutually exclusive events, which statement is true?
• Which probability concept uses the equation P[A] = (# of outcomes in which Event A occurs) / (Total number of outcomes in the sample space)?
• The probability of A given that B has occurred is denoted as which expression?
• Which nonparametric test is used for paired data?
• Which term describes an outcome that takes on a numerical value as a result of an experiment?
• Which sampling method requires representation from each stratum by drawing random samples from every stratum?
• Which central tendency measure is most affected by outliers?
• A particular result of an experiment. An example is rolling a pair of threes.
• Cohen's d is a measure of effect size for two means. Which formula correctly defines d?
• Which type of probability relies on experience and intuition to estimate probabilities?
• Which statistical approach updates the probability of hypotheses as new evidence becomes available?
• The Empirical Rule states that approximately 68% of data values lie within one standard deviation of the mean, about 95% within two, and about 99.7% within three.
• Which theorem states that as the sample size increases, the distribution of the sample means tends toward normal, regardless of the population distribution?
• Poisson distribution models count data observed in a fixed interval. What is the interpretation of its parameter λ?
• Which concept represents the probability of failing to reject a false null hypothesis?
• Which statement correctly describes Q2 in a data set that has been divided into four equal parts?
• If a value is one standard deviation above the mean, what is its z-score?
• The probability of failing to reject a false null hypothesis is called the:
• Number of distinct ordered arrangements for 4 distinct objects?
• Which of the following best describes the purpose of a boxplot?
• Which type of hypothesis test is used when the alternative hypothesis is expressed as not equal to a value?
• Which term refers to the probability of a single event?
• Which statement about data transformations in regression is true?
• What is the smallest level of significance at which the null hypothesis will be rejected, assuming the null is true?
• Chebyshev's Theorem provides a bound that, for any k > 1, at least a certain percent of data lie within k standard deviations of the mean. Which expression gives this bound?
• Which distribution displays the percentage of observations for each category relative to the total?
• Which statement about the correlation coefficient is true?
• In a chi-square test for independence, the null hypothesis states what?
• Explain the 68-95-99.7 rule for the standard normal distribution.
• Tells how many standard deviations a value is from the mean; if you have a mean of zero then you have a standard deviation of one
• Which distribution represents the theoretical distribution of a sample statistic across all possible samples?
• What is the mode and when is it most informative?
• Which graphical display shows the distribution of observations in each class with bars?
• The difference between the largest and smallest measurements in a data set is called the
• Which level of measurement involves strictly quantitative data and allows addition and subtraction?
• What is the standard error of the mean?
• What is the standard error of the mean and its formula?
• Which probability is calculated from observed frequencies in repeated trials?
• Which type of data uses descriptive terms to measure or classify things, not numerical values?
• Which sampling method selects every kth member of the population, with k approximately N/n?
• In a data set where quantities carry different weights, the average that accounts for these weights is called the
• For a Poisson distribution, which statement about λ is correct?
• In a Poisson Process, counts in disjoint time intervals are independent.
• Which statement best describes the median and when it is preferred over the mean?
• is a normal distribution with a mean equal to 0 and a standard deviation equal to 1.0.
• Which concept denotes a subset of the sample space comprising one or more outcomes that are of interest?
• In a right-skewed distribution with a few large values, which measure tends to be larger?
• Which statement is denoted by H0 and represents the status quo about the population mean?
• If the Pearson correlation coefficient is -0.85, what does this indicate?
• Which statement is denoted by H1 and represents the opposite of the null hypothesis?
• If a one-way ANOVA yields a significant F-statistic, what does this imply about the group means?
• What is the difference between a z-interval and a t-interval?
• If observations can belong to only one category, the categories are described as what?
• Which statement best describes the Central Limit Theorem?
• The observation that occurs most frequently in a data set is known as the
• Probability that relies on experience and intuition to estimate the probabilities.
• The interquartile range is defined as Q3 minus Q1. Which of the following is true about this statistic?
• Which concept determines the width of a confidence interval and is calculated using z-scores?
• The correlation coefficient measures what?
• Which statistic is most affected by outliers?
• Has the following characteristics: (1) the experiment consists of a fixed number of trials denoted by n; (2) each trial has only two possible outcomes, a success or a failure; (3) the probability of success and the probability of failure are constant throughout the experiment; (4) each trial is independent of any other trial in the experiment(coin toss). AKA Bernoulli process
• Distinguish correlation from causation.
• Which statement correctly defines a Type I error?
• The single value used to estimate a population parameter is called a
• What are residuals in regression?
• Which of the following does not directly affect the statistical power of a test?
• Which distribution models the count of events in a fixed interval when the mean count is the same for each interval?
• A measure of dispersion that describes how spread out the data are around the mean and is equal to the average of squared deviations is called the
• All the possible outcomes of the experiment.
• What is the meaning of statistical significance vs practical significance?
• Which error occurs when you fail to reject the null hypothesis when it is false?
• Which term describes the central point of a data set using a single representative value, with the mean as the most common example?
• Which term describes summarizing or displaying data so we can quickly obtain an overview?
• Is a sample in which every member of the population has an equal chance of being chosen
• Which term refers to data that uses numerical values to describe something of interest?
• For mutually exclusive events, which formula gives P(A or B)?
• What is the probability that the interval estimate will include the population parameter?
• The square root of the variance, representing the typical distance of data points from the mean, is the
• Which factor does NOT directly influence statistical power?
• A random variable is ____ if it is limited to assuming only specific integer values as a result of counting the outcome of an experiment.
• This type of probability observes the number of occurrences of an event through an experiment and calculates the probability from a relative frequency distribution.
• What graphical display uses bars of equal width to show the number of observations in each class?
• What is a paired t-test used for?
• An independent two-sample t-test can be used with which variance assumptions?
• In hypothesis testing, the decision rule 'reject H0 if the p-value is less than alpha' describes which concept?
• In a standard normal distribution, what are the mean and standard deviation?
• Splitting data values into stems and leaves, such as 8|00012338, is an example of which display?
• What is a sign test used for?
• How many ways to choose 3 items from 5 when order does not matter?
• If adding a predictor to a regression model increases R-squared but leaves adjusted R-squared nearly unchanged, what is the likely interpretation?
• Which term describes the spread of the sample means around the population mean?
• For a Binomial(n, p), what are its mean and variance?
• The mean, median, and mode are the same value. The distribution is bell-shaped and symmetrical around the mean. The total area under the curve is equal to 1. The left and right sides of the normal probability distribution extend indefinitely, never quite touching the horizontal axis.
• Which figure is known for merging science and statistics and promoting data-driven process improvement in manufacturing?
• Which concept represents the running total of percentages as you move down a frequency table?
• Which statement best describes Bayes' theorem in practice?
• How can data transformations affect regression analysis?
• As sample size increases, the standard error of the mean tends to which of the following?
• Which statement best describes the purpose of ANOVA when comparing three or more groups?
• In a normal distribution, which measures of central tendency are equal?
• Which term describes a range of values used to estimate a population parameter and is not necessarily tied to a specified confidence level?
• What is the process of measuring or observing an activity for the purpose of collecting data?
• Which branch of statistics makes claims about a population based on a sample?
• How do you compute the interquartile range (IQR) and what does it indicate?
• One or more outcomes that are of interest for the experiment and is/are a subset of the sample space.
• What term describes the pattern of sample means that would occur if many samples are drawn from the population?
• Which statistic measures the strength and direction of the linear relationship between two variables, with values ranging from -1 to +1?
• When would you use a chi-square goodness-of-fit test?
• Which pattern indicates heteroscedasticity?
• Which measure is the standard error of the proportion?