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WorksheetsBiostatistics 3 course
Total questions: 126
Worksheet time: 1hrs 3mins
The science that studies methods for processing the results of observations of mass random phenomena with a pattern is called:
mathematics
computer science
biology
statistics
chemistry
Science related to the development and use of statistical methods in scientific research in medicine, healthcare, and epidemiology:
judicial statistics
biological statistics
municipal statistics
industrial statistics
agricultural statistics
What are the two main groups into which all data is divided?
ordinal, discrete
qualitative, quantitative
ordinal, categorical
exact, continuous
binary, nominal
Quantitative data is divided into:
qualitative, quantitative
ordinal, categorical
continuous, discrete
binary, nominal
nominal, categorical
Qualitative data is divided into:
continuous, discrete
continuous, discrete
qualitative, quantitative
binary, nominal
exact, categorical
What is the name for data that takes strictly fixed numerical values?
Continuous
Discrete
Ordinal
Nominal
Qualitative
What are the names of features whose values can differ by any arbitrarily small amount?
Nominal
Ordinal
Continuous
Qualitative
Discrete
What feature takes one value from a finite number of obviously established gradations that cannot be ordered?
Quantitative
Continuous
Ordinal
Discrete
Continuous
Nominal data that are distributed into two non-overlapping categories:
quantitative
discrete
ordinal
binary
qualitative
A small group of randomly selected values of a random variable reflecting the essential features of the population is called:
population
interval series
normal population
sample
demographic population
A sample whose characteristics correspond to the population parameters:
random
normal
representative
reliable
parametric
What is the name of the dataset, where the elements are all residents of a given territory with a given pathology:
sample
interval
parametric
population
nomal
A quantity that, as a result of an experiment, can take values depends on various random events is called...
discrete.
random.
continuous.
absolute.
categorical
The quantity X (x1, x2, x3 …..xi……xn), which as a result of the experiment can take values within certain limits, it is not known in advance which one exactly. It is called... variable.
discrete.
random
continuous.
absolute.
categorical
What type of data does the number of doctor house calls refer to?
continuous.
discrete.
finite.
deterministic.
random
What values do discrete features take?
any values.
only fractional.
only integer numeric values.
both integer and fractional numeric values.
does not accept numeric values
A random variable is called discrete (discontinuous) if it takes...
any values within a certain interval.
qualitative features that are measured on a nominal scale.
countable numerical values
values from a finite number of established gradations.
ranked variation series
The quantitative assessment of the possibility of the occurrence of a given random event is…
frequency.
polygon.
cumulate.
ogive.
probability
Which of the following are basic statistical characteristics?
mean, variance, standard error.
Spearman correlation coefficient.
t-test, Fisher test.
significance level
Pearson correlation coefficient.
The difference between the maximum and minimum values of the observation frequencies in statistical data is...
median.
mean.
deviation.
range.
frequency
What is the name of the value of a random variable that divides the variation series into two equal parts?
mode.
quartile.
sample mean.
coefficient of variation
median
Variance, D(X) is
characteristic of the position of values of a random variable on the measurement axis.
characteristic of the dispersion of values of a random variable relative to the mean value.
characteristic of dispersion, introduced in order to get rid of the square of the unit of measurement.
relative measure of dispersion, expressed as a percentage.
most frequently occurring value of a random variable
Standard deviation is
characteristic of the position of values of a random variable on the measurement axis.
difference between the maximum and minimum values of the observation frequencies.
a statistic measuring the dispersion of a dataset relative to its mean.
relative measure of dispersion, expressed as a percentage.
most frequently occurring value of a random variable
Since the mean value is usually determined from a limited sample, and not from the population, it differs from the true (general) mean, that is, it has a certain error, called
Coefficient of variation.
Standard error of the mean.
Standard deviation.
Variance.
Mean
What does the quantity determine in the calculation of theoretical frequencies for a normal distribution?
mathematical constants
series variants
normal deviation coefficient
average value of variants
standard deviation
To find the theoretical probability, the following is used:
Sturgess's Formula
Coefficient of Variation
Standard Deviation
Gaussian Law
Interquartile Range
One of the properties of normal distribution
Хmean=R=Mo
Хmean=M(X)=D(X)
Хmean=Мо=Ме
Ме=D(X)=Mo
Mo=S=Хmean
Which of the following is an incorrect property of normal distribution?
Mean=Median=Mode
The curve is not symmetrical about the mean
It extends from (−∞) to (+∞)
This is a continuous probability distribution
The curve is shaped like a "bell"
What is the name of a bell-shaped graph in which the horizontal axis represents the effect size and the vertical axis represents the number of patients who experienced an effect of that size?
Frequency polygon
Survival curve
Gaussian curve
Frequency histogram
Pie chart
What is used to represent interval variation row?
Polygon
Cumulates
Empirical Distribution Function
Pie Chart
Histogram
The relative frequency is equal to
the length of a partial interval
the quotient of the interval frequency divided by the interval length
the frequency of a random variable value falling within an interval
the area of a curvilinear trapezoid within the boundaries of the interval ∆Х
the ratio of the number of cases in which a given result occurred to the total number of cases
A table containing partial intervals and their frequencies or relative frequencies is called:
random variable distribution curve
ranked series
statistical interval distribution row.
discrete distribution series
sample series
The ratio of the number of occurrences of an observed feature to the total number of objects in the population.
variant
frequency
range
size
relative frequency
Graphical representation of distributions of continuously varying features
polygon
histogram
median
mode
curve
The normal distribution has the property of equality of what numerical characteristics?
Mode, median, and standard deviation
Sample mean, variance, and standard deviation
Variance, standard deviation, and standard error of the mean
Sample mean, mode, and median
Standard deviation, standard error of the mean, and coefficient of variation
Parametric criteria are applied:
to distributions of the most varied forms.
when the population from which the sample is taken is normally distributed.
that the samples are obtained from homogeneous populations and, in particular, have equal means and medians.
on the homogeneity of two populations of pairwise related samples.
on the homogeneity of three populations of pairwise related samples
The Student's t-test is used to test the null hypothesis:
both means do not belong to the same population.
both means belong to the same population.
the means of infinite samples do not belong to the same population.
the population variances are not equal.
the factor variance is greater than the residual
One group of students had their heart rates measured before and after physical education classes. The resulting samples are
independent
both means belong to the same population.
inversely dependent
directly proportionally dependent
partially dependent
Student's t-test for assessing the difference in the mean values of two samples is used if they are distributed…
poisson
normal
smooth
binomial
exponential
The criteria used to test the assumption that the variances of two normally distributed populations are equal?
Pearson Chi-Square
Fisher
Mann-Whitney
Wilcoxon
Student
A statistical method used to compare the means of two groups of the same subjects.
factor analysis
cluster analysis
t-test for dependent samples
t-test for independent samples
discriminant analysis
Samples consisting of different objects, where the values of a random variable in one sample do not depend on its values in another sample
Dependent samples
Simple samples
Independent samples
Clustered samples
Regional samples
The researchers were faced with the task of comparing potassium in urine (g/day) in groups of healthy people and patients with pulmonary insufficiency. A preliminary test was conducted for the normality of the distribution of the random variable, the results of which showed that it was distributed normally. What method of analysis can be used to solve the task?
Fisher's test
Student's t-test
Mann-Whitney test
Wilcoxon test
McNimar test
A method of parametric statistical analysis used to compare the means of two normally distributed dependent groups:
factor analysis
non-proportional test
paired test
χ 2 test
goodness-of-fit test
In a study of the effects of a certain drug on 120 volunteers, the levels of liver enzymes in the blood were measured. What statistical method can be used to determine the effect of this drug on liver function if the liver enzymes being measured are known to have a normal distribution
Spearman test
Mann-Whitney test
Student's t-test for dependent samples
Wilcoxon test
Wald test
A method of statistical analysis used to compare means in two groups of different objects
discriminant analysis
t-test for independent samples
descriptive statistics
t-test for dependent samples
correlation analysis
What equality of indicators does F- Fisher criteria test?
means
population variances
standard deviations
mathematical expectations
medians
The Mann-Whitney test is:
parametric
nonparametric
trigonometric
logarithmic
systematic
When testing statistical hypotheses, the Mann-Whitney U test is used to:
dependent samples
independent samples
normally distributed samples
building a regression model
calculating the correlation coefficient
Nonparametric tests in statistics include:
Pearson goodness-of-fit test
Wilcoxon test
Fisher test
Shapiro-Wilk test
Student test
A test that allows one to determine whether two dependent samples belong to the same population
Wilcoxon W-test
Mann-Whitney U-test
McNimar Chi-square test
Pearson Chi-square test
Fisher F-test
to calculate the power of relationship between two qualitative features is used
Pearson correlation coefficient
Yula association coefficient
Spearman correlation coefficient
determination coefficient
regression equation coefficient
Nonparametric tests are used:
when the general population from which the sample is taken is distributed normally
to distributions of the most varied forms
when the general population is distributed according to the Gaussian law
when the variances of two normal populations are equal to each other
when the means of two samples belong to the same population
The Wilcoxon test is used to test the hypothesis H0:
that the population is distributed according to the Gaussian law
about the homogeneity of two populations with pairwise related samples
that the variances of two normal populations are equal to each other
that the means of two samples belong to the same population
about the equality of population variances for samples of the same size
The Mann-Whitney test is used to test the hypothesis H0:
that the population is distributed according to the Gaussian law
that the samples are obtained from homogeneous populations and, in particular, have equal means and medians
that the variances of two normal populations are equal to each other
that the means of the two samples belong to the same population
on the equality of population variances for samples of the same size
The number that an observation will receive in the set of all data after they have been ordered according to a certain rule is called:
sample
random number series
observation rank
absolute value data
variable series
When ranking pairwise differences for the Wilcoxon criterion, the following feature is observed:
the values of each sample are ranked separately
ranks are assigned sequentially from negative to positive values
negative and positive values are ranked separately
"zero" is not ranked
"zero" is assigned the first rank equal to "one"
Specify a nonparametric test designed to test the equality of medians of several samples:
Fisher test
Wilcoxon test
Kruskal-Wallis test
Student test
Pearson test
A criterion designed to study the determination of the direction of the shift in the values of the studied feature in two samples?
McNimar chi-square test
Fisher F-test
Student t-test
sign test
Kolmogorov-Smirnov test
A group of statistical criteria that do not include probability distribution parameters in the calculation and are based on the operation of frequencies or ranks:
parametric
nonparametric
sampling method
analysis of variance
regression analysis
A statistical hypothesis is...
assumption about the sample
assumption about the type of unknown of the problem
assumption about the type of distribution
expectation of random variable occurrence
methods of recording random variables
Goodness-of-fit test
for hypothesis testing about the assumed law of a known distribution
for hypothesis testing about relationship of variables
for hypothesis testing about equality of variances
for hypothesis testing about the assumed law of an unknown distribution
for hypothesis testing about equality of mean values
A type I error is
that the null hypothesis will be accepted when it is false
that neither hypothesis will be accepted
that the decision to accept the hypothesis is not wrong
that the null hypothesis will be rejected when it is true
that the solution to the problem is rejected
A type II error is
that the null hypothesis will be rejected when it is true
that neither hypothesis will be accepted
that the null hypothesis will be accepted when it is not true
that the decision to accept the hypothesis is not wrong
that the solution to the problem is rejected
During a statistical study, a decision was made to reject the null hypothesis when it was true. What type of error is allowed in this case?
type II error
systematic
type I error
relative
random
In a statistical study, a decision was made to accept the null hypothesis when it was not true. What type of error is allowed in this case?
type I error
systematic
relative
type II error
random
The probability of making a type I error is called
confidence interval
degrees of freedom
power of test
sampling function
significance level of test
The probability of not making a type II error is called
confidence interval
degrees of freedom
significance level of test
power of test
sampling function
Hypotheses tested for random variables distributed according to the normal law
random
parametric
complex
competing
nonparametric
A mathematical rule by which a statistical hypothesis with a given level of significance is accepted or rejected
significance level
criterion power
confidence interval
statistical test
coefficient of variation
The confidence interval for the difference of means lies in the positive range. Which hypothesis should the researcher most likely accept?
Alternative hypothesis about the difference of two sample statistics
Complex hypothesis about the difference of two population means
Alternative hypothesis about the difference of two population variances
Alternative hypothesis about the difference of two population means
Null hypothesis about the equality of two population means
Nominal features are
quantitative features whose values can differ by any arbitrarily small amount
qualitative features that take one value from a finite number of obviously established gradations that cannot be ordered
quantitative features whose values differ by no less than a unit of measurement of the feature
quantitative features that take any value from a finite number of obviously known values
qualitative features that can be ordered
To calculate the odds ratio (OR), the outcome and factor variables must be measured in
absolute scale
interval scale
ordinal scale
ratio scale
nominal scale
To what test does this formula apply?
Pearson's χ2 with Yates's correction
McNemar's χ2
Cramer's V
Pearson's χ2
Student's t
To what test does this formula apply
Pearson's χ2
McNemar's χ2
Pearson's χ2 with Yates's correction
Cramer's V
Student's t
To what test does this formula apply?
χ2 Pearson
χ2 Yates
χ2 McNemara
Cramer's V
Student's test
What is the number of degrees of freedom of the Pearson χ2 critical value for a 2*2 table?
0
1
2
3
4
What is the number of degrees of freedom of the Pearson χ2 critical value for a 3*3 table?
0
2
4
3
7
to test the hypothesis about the presence of a relationship between independent features based on the contingency table is
Wald-Wolfowitz test
Fisher test
Chi-square test
Wilcoxon test
Mann-Whitney test
What test is applied when the expected values in any of the cells are less than 5.
Chi-square test
Fisher's test
Fisher's exact test
Wilcoxon test
McNemer test
to test the hypothesis about the presence of a relationship between dependent features based on the 2*2 contingency table is
Wald-Wolfowitz test
Fisher test
McNemer test
Wilcoxon test
Mann-Whitney test
The ratio of the probability that an event will occur to the probability that the event will not occur
risk
sensitivity
chance
specificity
prevalence
risk of occurrence of the initial outcome
odds ratio
sensitivity
risk ratio
specificity
prevalence
The proportion of people in the population tested who are actually sick and who are identified as sick by the test results
sensitivity
risk
chance
specificity
prevalence
The proportion of people who test negative among all people who do not have the disease (condition)
risk
chance
sensitivity
prevalence
specificity
The Fisher test is:
nonparametric
trigonometric
logarithmic
parametric
systematic
In which cases is Pearson's correlation coefficient used to determine the relationship between random variables?
for ordinal features
for normally distributed features
for nominal features
for qualitative features
for independent features
Most often, the measure of dependence between variables is the correlation coefficient proposed by...
Kolmagorov-Smirnov
Mann-Whitney
Pearson
Wilcoxon
Fisher
In which cases is the Pearson correlation coefficient used to determine the relationship between random variables?
for qualitative features
for ordinal features
for nominal features
for quantitative features
for independent features
Pearson's linear correlation is applied
to determine the statistical significance of differences in qualitative features
to determine the relationship between two series of quantitative features with a normal distribution
to determine pairwise relationships between ordinal features
for multiple comparison
for nonparametric data
The parameter that characterizes the degree of linear relationship between two samples is called
variance
correlation coefficient
regression coefficient
Q coefficient
proportionality coefficient
Choose the interval on which the values of the correlation coefficient lie.
(0;1)
(-1;0)
(-1;1)
(-∞;+∞)
(0;+∞)
Sample coefficient of linear correlation r=0.99. Nature and strength of correlation:
positive, weak
negative, weak
positive, strong
positive, medium
strong
In which cases is the Spearman correlation coefficient used to determine the relationship between random variables?
for qualitative features
for independent features
for quantitative features
for independent samples
for normally distributed samples
Spearman's rank correlation is used
for determining pairwise relationships of quantitative features with normal distribution
for determining pairwise relationships of ordinal features
for determining statistical significance of differences in qualitative features
for multiple comparison
for nonparametric data
What is the relationship between the parameters if Spearman's rank correlation coefficient is 1?
there is a negative dependence
there is a positive dependence
there is a complete dependence
there is a curvilinear dependence
there is a power dependence
What is the relationship between the parameters if Spearman's rank correlation coefficient is 0?
complete relationship exists
inverse relationship exists
no relationship
direct relationship exists
curvilinear relationship exists
The condition for the Spearman rank correlation coefficient with a negative relationship:
|q |=1
|q |=0
q= - 0,55
q=0,23
q=0,75
What condition is satisfied for the Spearman rank correlation coefficient in the case of a positive relationship?
|q|=1
| q|=0
q= 0,55
q= - 0,23
q= - 0,75
The ratio of the correlation coefficient to the average error of the correlation coefficient is called
Student's coefficient.
correlation coefficient.
constant correlation.
reliability test
average error of the correlation coefficient.
Only the presence and direction of the relationship between correlated features can be represented using
scatterplots
tables
correlation coefficient
regression coefficient
regression constant
The term "survivability" refers to
number of patients who survived after some initial event
number of patients who died after some initial event
probability of surviving any point in time after some initial event
probability of surviving after admission to hospital
ratio of the number of survivors to the number of deaths after some initial event
Life time is
time of occurrence of some event
time of occurrence of an undefined event
time until a predetermined event occurs
time of expected undefined event
time from the start of occurrence and the end of an undefined event
Which method is more accurate in survival analysis?
Wald-Wolfowitz
Kaplan – Meyer
Cutler – Ederer
Berkson – Gage
Mann-Whitney
Which data is called censored?
real-time data
treatment duration with unknown data
data consisting of disease duration
data containing incomplete information
treatment duration with known data
Which data is called uncensored?
incomplete data
unknown data
duration of disease
duration of treatment
complete data
Survival characteristic is
Histogram
Survival line
Polygon
Survival curve
Cumulates
The median survival is
the value of the random variable that divides the sample in half
the probability of surviving to a certain time
the time by which exactly half of the subjects have survived
the most frequently occurring value of the random variable
the number of subjects who survived half of the study time
The variable "number of home doctor visits" is:
deterministic
continuous
nominal
discrete
random
The random variable "body temperature" belongs to:
discrete
continuous
nominal
ordinal
qualitative
Examples of ordinal data include:
blood type, number of doctor visits
stages of a disease, intensity of pain
gender, ethnic group
gender, number of children
temperature, blood type
The mean arterial pressure (mmHg) during the initial stage of shock was studied. What type of data does this characteristic represent?
categorical
discrete
ordinal
nominal
continuous
A graph that represents individual data points and is most suitable for small datasets is:
histogram
pie chart
scatter plot
box-and-whisker plot
stem-and-leaf plot
An example of an ordinal scale is:
gender and nationality
hair and eye color
weight and height
test scores
disability groups 1, 2, 3
Which of the following are quantitative characteristics?
Body temperature, social status
Nationality, type of activity
Quality of life, worker qualification
Population size, body weight
Eye color, hair color
Heart rate measurements (beats/min) for 1st-year students: 73, 73, 62, 67, 81, 63, 80, 64, 66, 67, 67, 66, 71, 68, 71, 76, 63, 66. What is the range?
12
20
11
19
0
A study of the health status of people aged 18 to 25 covered 1,000 students from various universities. What type of data set coverage is this?
average
general
selective
sample
volumetric
If the standard deviation is 6, what is the variance?
56
160
√(5)
36
3
Hematocrit indicators (red blood cells-plasma): 0.26, 0.12, 0.20, 0.28, 0.29, 0.21, 0.45, 0.38, 0.29, 0.24. Which of the following is the ranked series?
0.12; 0.20; 0.21; 0.24; 0.26; 0.28; 0.29; 0.29; 0.38; 0.45
0.26; 0.12; 0.20; 0.28; 0.29; 0.21; 0.45; 0.38; 0.29; 0.24
0.29; 0.21; 0.45; 0.38; 0.29; 0.24; 0.26; 0.12; 0.20; 0.28
0.28; 0.29; 0.29; 0.38; 0.45; 0.12; 0.20; 0.21; 0.24; 0.26
0.12; 0.20; 0.21; 0.24; 0.38; 0.45; 0.26; 0.28; 0.29; 0.29
A study of the health status of people aged 40 to 65 covered 2,000 cities worldwide. What type of data set coverage is this?
average
population
selective
sample
Find the standard error of the mean if the standard deviation is 35 and the sample size is 25:
7
8
2
22
23
The mean value that divides a dataset into two equal parts, with one part having values less than the mean and the other part having values greater than the mean, is called:
mode
median
sample arithmetic mean
weighted arithmetic mean
simple arithmetic mean
What is the proportion of units within ONE standard deviation under a normal distribution, in %?
100
95.4
99.7
68.3
1
What is the proportion of units within two standard deviations under a normal distribution, in %?
1
68.3
99.7
100
95.4
To assess the "normality" of a distribution more accurately, one can use metrics characterizing the shape of the curve:
Coefficient of variation, coefficient of skewness
Correlation coefficient, regression coefficient
Rank correlation coefficient, coefficient of kurtosis
Coefficient of skewness, coefficient of kurtosis
Regression coefficient, rank correlation coefficient
What does the value of π,е determine in the calculation of theoretical frequencies for the normal distribution?
normalized deviation
series variants
average value of variants
standard deviation
mathematical constants
