Which of the following are correct?

(a) Quartile deviation is a measure of variability taken about median.

(b) Coefficient of variation is the percentage variation of the group adjusted with median.

(c) In positive skewness, test is too easy for the subjects.

(d) Degree of freedom can be defined as the number of independent vaiables which constitutes a statistic.

Choose the correct option from the given codes:

Statistical measures are used in data analysis to describe and summarize data, identify patterns and relationships, and make inferences about populations based on sample data. These measures include measures of central tendency, measures of variability, and measures of association or correlation.

 Key Points The given options pertain to statistical measures and concepts commonly used in data analysis.

• Quartile deviation is a measure of variability taken about the median.
  • It is calculated as half the difference between the upper and lower quartiles, and provides a measure of spread around the median.
• Degrees of freedom refer to the number of independent observations or variables in a statistical analysis that are available to vary.
  • It is an important concept in hypothesis testing, as it determines the critical values for a given level of significance, and affects the precision of estimates of population parameters.

Confusion Points

• Option (b) is incorrect. Coefficient of variation is the ratio of the standard deviation to the mean, expressed as a percentage.
  • It is used to compare the variability of two or more data sets that have different means or units of measurement.
• Option (c) is also incorrect. Positive skewness indicates that the distribution is skewed to the right, with a longer tail on the right side of the curve.
  • This would imply that the test is more difficult for subjects who score high, rather than easy.