The random error in the arithmetic mean of $100$ observations is $x$; then random error in the arithmetic mean of $400$ observations would be

Explain uncertainty or error in given measurement by suitable example.

Resistance of a given wire is obtained by measuring the current flowing in it and the voltage difference applied across it. If the percentage errors in the measurement of the current and the voltage difference are $3\%$ each, then error in the value of resistance of the wire is ........ $\%$

The distance $s$ travelled by a particle in time $t$ is $s=u t-\frac{1}{2} \,g t^{2}$. The initial velocity of the particle was measured to be $u=1.11 \pm 0.01 \,m / s$ and the time interval of the experiment was $t=1.01 \pm 0.1 \,s$. The acceleration was taken to be $g=9.8 \pm 0.1 \,m / s ^{2}$. With these measurements, the student estimates the total distance travelled. How should the student report the result?

The resistance $R =\frac{V}{I}$ where $V= 100  \pm 5 \,volts$ and $ I = 10  \pm 0.2$ amperes. What is the total error in $R$ ......... $\%$

A simple pendulum is being used to determine the value of gravitational acceleration $\mathrm{g}$ at a certain place. The length of the pendulum is $25.0\; \mathrm{cm}$ and a stop watch with $1\; \mathrm{s}$ resolution measures the time taken for $40$ oscillations to be $50\; s$. The accuracy in $g$ is  ....... $\%$