The answer would be B.
<span>
Standard deviation basically measures how spread out the values are. Without solving, you can easily tell which one among your choices have a smaller deviation. The closer the values are to each other the smaller the standard deviation. The values of choice B are the closest together, so you can assume that they have the smallest standard deviation. </span>
Answer:
Arrange an annual service. Treat your boiler like your car. ...
Keep your boiler clean. ...
Bleed your radiators. ...
Top up the pressure. ...
Use a Powerflush. ...
Insulate your pipes. ...
Turn the heating on. ...
If all else fails…
Explanation:
Harnessing the sun's energy to produce heat or electricity is : A. Non - Polluting
This energy generating method will cause no dangerous emission for environment (unlike the one that came from fossil fuel), but the energy that produced from the sun tend to be more expensive so it's still not widely used
hope this helps
