Statistics

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

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.

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.
\(2\: 520\, \mathrm{g}\)
\(2\: 540\, \mathrm{g}\)
\(2\: 480\, \mathrm{g}\)
\(2\: 460\, \mathrm{g}\)

9000139501

Level: 
A
Ten apples in a box have average mass \(200\, \mathrm{g}\). We remove one apple of the mass \(200\, \mathrm{g}\) from the box. What is the change in the average mass of the apples from the box?
The average mass of the apples does not change.
The average mass of the apples decreases by \(20\, \mathrm{g}\).
The average mass of the apples increases by \(20\, \mathrm{g}\).
There is not enough information to solve this problem.

9000139504

Level: 
A
The average salary of five employees is \(3\: 000\, \mathrm{Euro}\). This group of the employees is expanded by one new person. The salary of the new person is \(2\: 400\, \mathrm{Euro}\). Find the change in the average salary of this group.
The average salary decreases by \(100\, \mathrm{Euro}\).
The average salary decreases by \(480\, \mathrm{Euro}\).
The average salary increases by \(400\, \mathrm{Euro}\).
The average salary increases by \(480\, \mathrm{Euro}\).

9000139506

Level: 
A
There are eight mandarins of average mass \(90\, \mathrm{g}\) in the box. We got two another mandarins and add them to the box. The new average mass of the mandarins in the box is \(92\, \mathrm{g}\). Find the average mass of the two added mandarins.
\(100\, \mathrm{g}\)
\(92\, \mathrm{g}\)
\(96\, \mathrm{g}\)
\(106\, \mathrm{g}\)

9000139509

Level: 
A
The average year income in a company was \(200\: 000\, \mathrm{Euro}\) two years ago. This income increased by \(10\%\) a year ago and by \(80\: 000\, \mathrm{Euro}\) this year. Find the average percentage increase in the average income per one year and round to the nearest percent.
\(22\%\)
\(23\%\)
\(25\%\)
\(50\%\)