biostats

Which one of the following best identifies a characteristic of a t-distribution in terms of how it differs from the standard normal distribution (z-distribution)?

Accounts for uncertainty due to sampling error.

For the characteristic provided, identify if it applies to t-tests only, analysis of variance (ANOVA) tests only, both t-tests and analysis of variance tests, or neither t-tests nor ANOVA. Assumes sample units are independent of one another and drawn randomly from the statistical population.

Both

Which of the following are true of the concept of a test statistic? Select all that apply.

Calculated from sample data Gets compared against a corresponding null distribution.

The general linear model as a basis for ANOVA is conceptually drawn from which one of the following? Select one

equation of a line

Which of the following are measures of variation (i.e., spread), but not uncertainty, that can be calculated from sample data? Select all that apply.

Interquartile range Standard deviation

Which two of the following are needed to identify the F-critical value for a particular study? Select two.

Numerator degrees of freedom, Denominator degrees of freedom

In meta-analysis, the response variable used for statistical testing is

a calculated effect size

The chi-square probability distribution is a ________ probability distribution.

continuous

Which of the following are quantities are used to calculate slope (b)? Select all that apply.

deviation of Y deviation of X total sum of squares for X

General linear models do not assume samples representing unique treatments have been randomly selected.

false

Which one of the following terms best describes research into the methods for, evaluation of, and incentives driving research practice?

meta-research

Which of the following tests can be used to evaluate whether samples meet the assumption of normality? Select all that apply.

Shapiro-Wilk test

Under the null hypothesis, the F-ratio is expected to be approximately equal to or less than 1 . Select the most appropriate answer from the dropdown.

1

The probability of a randomly selected observation falling within the mean plus-or-minus 1.96 standard deviations (m ± 1.96s) is ______ in a normal probability distribution.

.950

In a normal probability distribution, both skewness and excess kurtosis have a value of

0

You sample 20 individuals to see if they have the MC1R gene on chromosome 16. The gene is present in only 2 individuals. In what percentage of the sample was the MC1R gene present?

10

In a regression analysis with 20 sample units and 1 predictor variable, there would be ____ residual degrees of freedom?

18

In a regression analysis with 20 sample units and 1 predictor variable, there would be ____ total degrees of freedom?

20

The methods section of a journal article states that the researchers tested 4 treatments using a randomized complete block experimental design and analyzed using ANOVA methods. They also state that they had 5 blocks. What is the total sample size for this experiment?

20

The methods section of a journal article states that the researchers conducted a 3 x 4 factorial analysis of variance with regard to factors A and B, respectively. There were 10 replicates of each treatment. How many levels of factor B were included in this study?

4

Which of the following are stages of the data life cycle? Select all that apply.

Collecting data Analyzing data Preserving data Integrating data

Which of the following are acceptable forms of data analysis? Select all that apply.

Calculating descriptive statistics, such as mean and standard deviation. Combining data from similar but separate studies to look for broad patterns and propose new hypotheses. Feeding data from a study into an established mathematical model to predict a longer-term outcome. Conducting inferential statistics to test hypotheses.

You have a dataset from an experiment with one factor and 3 groups for that factor. You find that data in each group is normal distributed and has equal variances. How do you proceed?

Conduct an ANOVA using the raw data values

You conduct a survey of patients to examine whether there is a relationship between low density lipoprotein cholesterol concentration and blood pressure. What type of analysis would be most appropriate?

Correlation

Which of the following terms is calculated by finding the squared deviations between individual observations and the group means and then summing them for all observations in the study?

Error sum of squares

Which of the following can be used to evaluate whether there is publication bias for a given topic?

Fail-safe number, funnel plot

Which of the following are true of the concept of a test statistic? Select all that apply

Gets compared against a corresponding null distribution., Calculated from sample data

When doing a systematic review or meta-analysis, which of the following is the first step that should be completed among those listed?

Identify a specific question to be addressed

The non-parametric equivalent of a one-way ANOVA is the

Kruskal-Wallis test

Which of the following distinguishes measures of variation (i.e., spread) from measures of uncertainty? Select the one best answer from the following.

Measures of uncertainty take into account sample size.

If data are not normally distributed and a data transformation does not improve normality, which of the following are plausible options for further statistical testing? Select all that apply.

Permutation methods Non-parametric methods

Which of the following theoretical probability distributions do not assume sample units are randomly selected and independent when applied to statistical hypothesis testing? Select all that apply.

Poisson distribution correct None of the above Binomial distribution Normal distribution All of the above

Which of the following can be used to evaluate the normality of a sample? Select all that apply.

Quantile-quantile plot Histogram Kurtosis Shapiro-Wilk test Skewness

Which of the following are associated with statistical power? Select all that apply.

Represents probability of rejecting the null hypothesis when it is false in reality. Can be used to determine sample size when designing an experiment. Can be used to determine if sample size was large enough when interpreting the meaning of statistical tests

Which of the following best describes the importance of residuals in linear regression?

Represents variation in the response variable not explained by the explanatory variable.

Which one of the following best represents why the standard error of the mean (SEM) is used as the denominator of the equation for a Z score calculated from a sampling distribution? Select one.

SEM is the standard deviation of the sampling distribution

Which of the following are assumptions of neither the chi-square goodness-of-fit test nor the chi-square contingency test? Select all that apply.

Samples were observed non-randomly.

Which of the following are benefits of rigorous data management? Select all that apply.

Scientific community and general public have more confidence in results published from well-managed data. Data can be used by someone else in the future. Data are more likely to be free of errors. Peers can evaluate legitimacy of data.

Which of the following best represents the null hypothesis (H0) for the test of skewness? Select one.

Skewness is equal to zero.

Which of the following best defines the term "publication bias"?

Studies are more likely to be published if they find significant results.

You conduct an experiment in which you compare the response of a treatment group to a control group that did not receive the treatment. You are using a significance level (alpha) of 0.05. After analyzing the data, the statistical test results in a p-value of 0.062. Which of the following would you conclude based on this information? Select all that apply.

There is not a statistically significant difference between groups., Fail to reject the null hypothesis

Which of the following terms is calculated by finding the squared deviations between individual observations and the grand mean and then summing them for all observations in the study?

Total sum of squares

Which of the following are disadvantages of a study design that produces paired data?

Violates the assumption of independence between sample means

Which of the following tests assume data for both samples are normally distributed? Select all that apply.

Welch's t-test Student's t-test

Which of the following are appropriate steps in the experimental process when the number of tails being tested can be determined? Select all that apply.

When identifying the hypotheses, When articulating the research question

Which of the following are assumptions for regression analysis? Select all that apply.

X- and Y-variables exhibit a linear relationship Y-residuals have equal variances over the range of X Y-residuals are normally distributed Sample units are independent of one another

A one-sample t-test does not require sample units to represent randomly selected and independent individuals from the statistical population.

false

All Z tables only provide probabilities for the area under the curve from a critical value to the upper tail (Pr[Z > critical value]) of a standard normal distribution.

false

Sample size calculations can be performed for many different types of data using a single equation.

false

The Mann-Whitney U-test assigns the lowest rank to the smallest value in the dataset, while the Wilcoxon Rank Sum test assigns the highest rank to the smallest value.

false

The chi-square goodness-of-fit test assumes that none of the mutually exclusive categories have an expected frequency less than 1, while the chi-square contingency analysis does not have this assumption.

false

The null hypothesis of the chi-square goodness-of-fit test is that the mean frequency observed in a sample is equal to the mean frequency expected assuming only that observations are distributed proportionally.

false

A meta-analysis project in which all studies evaluated are expected to share one same treatment effect with only sampling error contributing to differences in effect sizes between studies would be analyzed using which one of the following?

fixed-effects model

Which one of the following terms best describes statistical tools that can be used to analyze outcomes of multiple studies relating to the same question?

meta-analysis

For a given treatment, the ratio of the probability of success to the probability of failure is called the

odds

The ratio of the probability of success in one treatment to the probability of success in a different treatment in the same study is called the

odds ratio

The ratio of the probability of success in one treatment to the probability of success in a different treatment in the same study is called the ___________.

odds ratio

Based on the null and alternative hypotheses below would a one-tailed or two-tailed test be most appropriate? Null hypothesis: The difference between the responses of treatment and control groups is less than or equal to zero. Alternate hypothesis: The difference between the responses of treatment and control groups is greater than zero.

one-sided test

Which of the following are needed to calculate a standard normal deviate (Z score)? Select all that apply

population standard deviation population mean observed value or value of interest

You conduct an experiment of randomly selected patients having a range of low density lipoprotein (LDL) cholesterol concentrations and monitored their blood pressure to examine if LDL cholesterol causes higher blood pressure. What type of analysis would be most appropriate?

regression

Which of the following analyses could be used to assess linear relationships between two continuous numeric variables? Select all that apply.

regression, correlation

Is the interquartile range of a dataset a measure of central tendency or spread?

spread

The test statistic for a correlation analysis is

t-statistic

For the characteristic provided, identify if it applies to t-tests only, analysis of variance (ANOVA) tests only, both t-tests and analysis of variance tests, or neither t-tests nor ANOVA. Can test the null hypothesis that 2 sample means are equal.

t-test and anova

Which of the following best represents assumptions non-parametric statistical tests

there is no assumed probability distribution

Which of the following quantities are used to calculate the standard error for Pearson's correlation coefficient (r)? Select all that apply.

total sum of squares for Y correlation coefficient deviation of Y df

A p-value indicates the probability of getting a test statistic as extreme or more extreme assuming the null hypothesis is true.

true

Assumptions of general linear models are the same as those for one-way ANOVA.

true

Both the chi-square goodness-of-fit test and the chi-square contingency analysis assume that 80% or more of mutually exclusive categories have an expected frequency of 5 or greater

true

Chi-square tests compare observed frequencies to expected frequencies. The p-value is determined from comparing a chi-square test statistic to the the chi-square probability distribution.

true

For a given study, if the t-statistic is larger than the t-critical then the null hypothesis will be rejected.

true

Sample data do not need to be perfectly normally distributed in order to proceed with additional statistical tests.

true

The binomial test would be appropriate for testing the following null hypothesis: The probability of winning the lottery is less than 0.1%.

true

The null hypothesis of the chi-square goodness-of-fit test is that the frequency distribution observed in a sample does not differ from the frequency expected under a given theoretical probability distribution.

true

The use of fixed- or random-effects models in meta-analysis is analogous to their use in analysis of variance.

true

In an experiment testing whether two drugs interact with one another to influence patient outcomes, which one of the following experimental designs would be most appropriate to use for statistical analysis? Select one.

two-way factorial analysis of variance

The Tukey-Kramer adjustment is used to maintain the Type I error rate for which type of comparisons?

unplanned

If a researcher conducts an experiment with 1 fixed factor consisting of 5 treatments and wants to compare means of all 5 treatments against one another, what type of comparison of those treatments would they do if their overall ANOVA is not significant?

would not be appropriate

The methods section of a journal article states that the researchers conducted a 3 x 4 factorial analysis of variance with 10 replicates of each treatment. In the results section, they indicate the test had a total of 119 degrees of freedom. Is this correct?

yes