# A student measuring the diameter of a pencil of circular cross-section with the help of a vernier scale records the following four readings $5.50 \mathrm{~mm}, 5.55 \mathrm{~mm}, 5.45 \mathrm{~mm}$, $5.65 \mathrm{~mm}$, The average of these four reading is $5.5375 \mathrm{~mm}$ and the standard deviation of the data is $0.07395 \mathrm{~mm}$. The average diameter of the pencil should therefore be recorded as:

Question:

A student measuring the diameter of a pencil of circular cross-section with the help of a vernier scale records the following four readings $5.50 \mathrm{~mm}, 5.55 \mathrm{~mm}, 5.45 \mathrm{~mm}$, $5.65 \mathrm{~mm}$, The average of these four reading is $5.5375 \mathrm{~mm}$ and the standard deviation of the data is $0.07395 \mathrm{~mm}$. The average diameter of the pencil should therefore be recorded as:

1. $(5.5375 \pm 0.0739) \mathrm{mm}$

2. $(5.5375 \pm 0.0740) \mathrm{mm}$

3. $(5.538 \pm 0.074) \mathrm{mm}$

4. $(5.54 \pm 0.07) \mathrm{mm}$

JEE Main Previous Year Single Correct Question of JEE Main from Physics Physical World, Units and Measurements chapter.

JEE Main Previous Year Sep. 06, 2020 (II)

Correct Option: 4

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