Q 1. Property of mean
1. The sum of the deviations of each value from the mean is
always zero.
2. it includes every value in your data set as part of the
calculation.
3. it produces the lowest amount of error from all other values
in the data set.
from 2 properties option d is the right answer.
Q2. Chebyshev's theorem applies to all data set, not only
normally distributed data sets. According to this theory, the
portion of any set of data within K standard deviations of
the mean is always at least 1-1/K^{2}, K
>1.
Q.4 The mean, median, and mode of a normal distribution are
equal. This is because the normal distribution curve is symmetric
and unimodal means has only one peak.