Expenditure | Number of families |
1000-1500 | 24 |
1500-2000 | 40 |
2000-2500 | 33 |
2500-3000 | 28 |
3000-3500 | 30 |
3500-4000 | 22 |
4000-4500 | 16 |
4500-5000 | 7 |
Solution:
From the given information the modular class is 60–80.
l = 60,
The frequencies are:
fm = 61, f1 = 52, f2 = 38 and h = 20
The equation to discover the mode is
\[\begin{array}{*{35}{l}}
Mode\text{ }=\text{ }l+\text{ }\left[ \left( fm-f1 \right)/\left( 2fm-f1-f2 \right) \right]\times h \\
~ \\
\end{array}\]
Substitute the qualities in the equation, we get
\[\begin{align}
& \begin{array}{*{35}{l}}
Mode\text{ }=60+\left[ \left( 61-52 \right)/\left( 122-52-38 \right) \right]\times 20 \\
~ \\
Mode\text{ }=\text{ }60+\left( \left( 9\text{ }x\text{ }20 \right)/32 \right) \\
~ \\
Mode\text{ }=\text{ }60+\left( 45/8 \right)\text{ }=\text{ }60+\text{ }5.625 \\
\end{array} \\
& \\
\end{align}\] Along these lines, modular lifetime of the parts = 65.625 hours.