JEE Main · 2024 · 06 Apr 2024 · Shift 1 · Statistics

WhatsApp Email
The mean and standard deviation of 20 observations are found to be 10 and 2, respectively. On rechecking, it was found that an observation by mistake was taken 8 instead of 12. The correct standard deviation is
  1. (A)
  2. (B)1.94
  3. (C)✓ Correct
  4. (D)1.8

Answer: (C)

Solution

, and variance .
Correcting : , mean ; .
Correct variance , so SD

JEE Main · 2024 · 06 Apr 2024 · Shift 1 · Single correct option

More JEE Main questions on Statistics

  1. Let the mean and variance of 7 observations , be 8 and 16 respectively. Two numbers are chosen from one after another without replacement, then the probability, that the smaller number among the two chosen num …
    JEE Main 2026View solution →
  2. If the mean deviation about the median of the numbers is 500, then is equal to :
    JEE Main 2026View solution →
  3. Let the mean and variance of 8 numbers be and , respectively. Then the mean of 4 numbers is:
    JEE Main 2026View solution →
  4. If the mean and the variance of the data

    \begin{tabular}{|l|c|c|c|c|}
    \hline Class & & & & \\
    \hline Frequency & 3 & & 4 & 7 \\
    \hline
    \end{tabular}

    are and 19 respectively, then the value of is
    JEE Main 2026View solution →
  5. The mean and variance of a data of 10 observations are 10 and 2, respectively. If an observation in this data is replaced by , then the mean and variance become 10.1 and 1.99, respectively. Then equals.
    JEE Main 2026View solution →
  6. Let and for some , . If the mean and variance of the elements of Y are 30 and 750, respectively, th …
    JEE Main 2026View solution →