Answer
Tap:
$Mean=7.50$, $Median=7.485$ and $Mode=7.47$
Bottled:
$Mean=5.194$, $Median=5.22$ and $Mode=5.26$
The bottled water is acidic and tap is only a little alkaline. In both cases, $mean\approx median$
Work Step by Step
Tap:
- In ascending order : 7.10, 7.45, 7.45, 7.47, 7.47, 7.47, 7.50, 7.52, 7.56, 7.64, 7.68, 7.69
$Mean=\frac{7.10+2\times7.45+3\times7.47+7.50+7.52+7.56+7.64+7.68+7.69}{12}=7.50$
There are 12 observations (even). The median is the mean of the sixth and seventh observations.
$Median=\frac{7.74+7.50}{2}=7.485$
Mode: 7.47 has the highest frequency: 3
Bottled:
- In ascending order : 5.02, 5.09, 5.13, 5.15, 5.20, 5.21, 5.23, 5.24, 5.26, 5.26, 5.26, 5.28
$Mean=\frac{5.02+5.09+5.13+5.15+5.20+5.21+5.23+5.24+3\times5.26+5.28}{12}=5.194$
There are 12 observations (even). The median is the mean of the sixth and seventh observations.
$Median=\frac{5.21+5.23}{2}=5.22$
Mode: 5.26 has the highest frequency: 3
