Question

the table shows the scores of 20 people who took the paramedics licensing test. Find the mean and the standard deviation of the data. the deviation answer needs to be rounded to three decimal places as needed.

Answer 1

a) Mean = 76

b) Standard deviation = 6.728

Explanation:

The data set has frequency. So we will apply the formula:

$\text{Mean = }\frac{\sum ^{}_{}fx}{\sum ^{}_{}f}$$\begin{gathered} \text{Mean = }\frac{(69\times7)\text{ + (70}\times1)+(75\times3)\text{ + (81}\times6)\text{ + (82}\times2)+\text{ (92}\times1)}{7\text{ + 1 + 3+6+2+1}} \\ \text{Mean = }\frac{483\text{ + 70}+225\text{ + 486 + 164}+\text{ 9}2}{7\text{ + 1 + 3+6+2+1}} \\ \text{Mean = }\frac{1520}{20} \\ \text{Mean = 76} \end{gathered}$

To get the standard deviation, we will apply the formula:

$\begin{gathered} \sigma\text{ = }\sqrt[]{\frac{\sum^{}_{}f(x_i-\mu)^2}{n\text{ - 1}}} \\ \text{where }\sigma\text{ = standard deviation} \\ \mu\text{ = mean, }x_i\text{ = values of x} \\ n\text{ = }\sum ^{}_{}f=20 \end{gathered}$$\begin{gathered} \sigma\text{ = }\sqrt[]{\frac{860}{20-1}} \\ \sigma\text{ = }\sqrt[]{\frac{860}{19}} \\ \sigma\text{ = }\sqrt[]{45.2632} \\ \sigma\text{ = 6.7}28 \\ \\ \text{Standard deviation = 6.7}28 \end{gathered}$