Measures of Central Tendency Quiz

When calculating the mean from a frequency table (not grouped), what is the first step?

• Add up the frequency column

• Add an extra column to the table and label as \( f \times x \)

• Divide the total of the third column by the total frequency

• Calculate the midpoint of the class intervals

If you remove a value that is less than the mean, what happens to the mean?

• The mean increases.

• The mean decreases.

• The mean stays the same.

• The mean becomes the median.

How is the Lower Quartile (LQ) calculated for discrete data?

• LQ = ½ (n+1)th value

• LQ = ¼ (n+1)th value

• LQ = ¾ (n+1)th value

• LQ = n/2 value

For grouped data, what is the first step in finding the Lower Quartile (LQ) and Upper Quartile (UQ)?

• Use the formulae to find the positions for LQ and UQ

• Draw lines from the 25% and 75% marks on the y-axis

• Draw your CF curve

• Put the data in order, smallest to largest

What is the Interpercentile Range (IPR)?

• The difference between the highest and lowest values in a data set.

• The difference between 2 percentiles.

• The sum of all percentiles in a data set.

• The average of all percentiles in a data set.

What is the correct order of steps when using the second formula for calculating the standard deviation from a frequency table?

• Add three columns, calculate the mean, substitute values into the formula.

• Calculate the mean, add three columns, substitute values into the formula.

• Substitute values into the formula, add three columns, calculate the mean.

• Add three columns, substitute values into the formula, calculate the mean.

When interpreting box plots, what should you compare for a measure of average?

• Range

• Interquartile range (IQR)

• Median

• Standard deviation

What does skewness describe in a data distribution?

• The central tendency of the data

• The shape of the distribution and how the data is spread out

• The range of the data

• The variance of the data

When comparing data sets, which measure of spread is used to determine how spread out or consistent the data is?

• Range/IQR/SD

• Mean/Median/Mode

• Skewness

• None of the above

What does a lower standard deviation (SD) indicate about the values in a data set?

• Values are more spread out.

• Values are closer to the mean and therefore similar.

• Values are higher.

• Values are lower.