Question

The ages of 11 students enrolled in an on-line macroeconomics course are given in the following steam-and-leaf display:

Stem Leaf
----- -----------------------
1 9 9
2 1 5 5 8 9
3 0 1 2
4 0
Here 1|9 implies 19 years (i.e. the stem represents tens and leaf represents units).

The standard deviation of the age distribution is years. [Answer up to four digits after decimal]

Incorrect. Tries 2/3 Previous Trie

Answer 1

Answer:

The standard deviation of the age distribution is 6.2899 years.

Step-by-step explanation:

The formula to compute the standard deviation is:

$SD=\sqrt{\frac{1}{n}\sum\limits^{n}_{i=1}{(x_{i}-\bar x)^{2}}}$

The data provided is:

X = {19, 19, 21, 25, 25, 28, 29, 30, 31, 32, 40}

Compute the mean of the data as follows:

$\bar x=\frac{1}{n}\sum\limits^{n}_{i=1}{x_{i}}$

  $=\frac{1}{11}\times [19+19+21+...+40]\\\\=\frac{299}{11}\\\\=27.182$

Compute the standard deviation as follows:

$SD=\sqrt{\frac{1}{n}\sum\limits^{n}_{i=1}{(x_{i}-\bar x)^{2}}}$

      $=\sqrt{\frac{1}{11-1}\times [(19-27.182)^{2}+(19-27.182)^{2}+...+(40-27.182)^{2}]}}\\\\=\sqrt{\frac{395.6364}{10}}\\\\=6.28996\\\\\approx 6.2899$

Thus, the standard deviation of the age distribution is 6.2899 years.