The total blood cholesterol level was measured for each of  21adults. Here are the  21 measurements (in mg/dL). 129, 144, 159, 162, 163, 168, 183, 184, 184, 185, 186, 195, 196, 197, 198, 207, 209, 221, 222, 234, 246.(a) Which measures of central tendency do not exist for this data set? Choose all that apply.

Mean

Median

Mode

None of these measures

(b) Suppose that the measurement 129 (the smallest measurement in the data set) were replaced by 52. Which measures of central tendency would be affected by the change? Choose all that apply.

Mean

Median

Mode

None of these measures

(c) Suppose that, starting with the original data set, the smallest measurement were removed. Which measures of central tendency would be changed from those of the original data set? Choose all that apply.

Mean

Median

Mode

None of these measures

(d) Which of the following best describes the distribution of the original data? Choose only one.

Negatively skewed

Positively skewed

Roughly symmetrical