Statistics

1003029401

Level: 
B
Wooden boards were expected to be cut to the same length. After their cutting the resulting measured lengths are: \( 2{.}00;\ 2{.}02;\ 2{.}05;\ 2{.}02;\ 2{.}08;\ 2{.}11 \) (in meters). We use the standard deviation of board lengths to describe (quantify) the accuracy of cutting. Find the standard deviation of board lengths rounded to four decimal places.
\( 0{.}0382\,\mathrm{m} \)
\( 0{.}0381\,\mathrm{m} \)
\( 0{.}0014\,\mathrm{m} \)
\( 0{.}0015\,\mathrm{m} \)

9000153308

Level: 
B
Statistical file contains repeating measurements of a body mass in kilograms. Find the change in the coefficient of variation if we convert all data in the file to grams.
The coefficient of variation does not change.
The coefficient of variation becomes bigger.
The coefficient of variation becomes smaller.

9000153310

Level: 
B
Student did repeated measurements of the coefficient of friction, which is a dimensionless quantity. The mean of the measurements is \(0.6\) and the coefficient of variation (relative error) \(10\%\). From statistics it is known that with a probability nearly \(100\%\) the value of the coefficient is in the interval centered at the mean and having radius equal to the triple of the standard deviation. Find the upper bound of this interval.
\(0.78\)
\(0.18\)
\(0.42\)
\(0.66\)

9000153304

Level: 
B
Two students performed repeated measurements of the same length. After evaluating statistical characteristics they got equal means of the length. Which of the following statement is true? (Remark: The accuracy is determined by the coefficient of variation.)
There is not enough information to compare the accuracy of both measurements.
One of the students measured with a better accuracy than the other.
Both students did their measurements with the same accuracy.

9000153305

Level: 
B
Two students performed repeated measurements of the same length. After evaluating statistical characteristics they got equal standard deviations. Which of the following statement is true? (Remark: The accuracy is determined by the coefficient of variation.)
There is not enough information to compare the accuracy of both measurements.
One of the students measured with a better accuracy than the other.
Both students did their measurements with the same accuracy.

9000153306

Level: 
B
Two students performed repeated measurements of the same length. After evaluating statistical characteristics they got equal means and also equal standard deviations. Which of the following statement is true? (Remark: The accuracy is determined by the coefficient of variation.)
Both students did their measurements with the same accuracy.
There is not enough information to compare the accuracy of both measurements.
One of the students measured with a better accuracy than the other.
The stated question is irrelevant, two different statistical files cannot share their means and their standard deviations.

9000153301

Level: 
B
A student performed repeated measurements of a length (in meters) and evaluated the main statistical characteristics: mean, standard deviation, variance and the coefficient of variation. Which of these characteristics has it's unit square meter?
variance
standard deviation
mean
coefficient of variation

9000153302

Level: 
C
A student performed repeated measurements of a length (in meters) and evaluated the main statistical characteristics: mean, standard deviation, variance and the coefficient of variation. Which of these characteristics is dimensionless?
coefficient of variation
variance
standard deviation
mean

9000153303

Level: 
C
A student performed repeated measurements of a length (in meters) and evaluated the main statistical characteristics: mean, standard deviation, variance and the coefficient of variation. Unit of which of these characteristics is meter?
the mean and the standard deviation
only the variance
only the standard deviation
only the mean
the standard deviation and the variance
the standard deviation, the variance and the coefficient of variation

9000139507

Level: 
A
The average mass of five melons is \(2\: 400\, \mathrm{g}\). We have to add another melon such that the new average value of all six melons will be \(2\: 420\, \mathrm{g}\). Find the mass of the sixth melon.
\(2\: 520\, \mathrm{g}\)
\(2\: 540\, \mathrm{g}\)
\(2\: 480\, \mathrm{g}\)
\(2\: 460\, \mathrm{g}\)