A round number is less accurate, but easier to use, because you get rid of certain decimals.
There are some rules to do this:
If we want to round a number to the nearest tenth, we have to look what's the unit after it, if that unit is more than 5, we round the tenth to the upper number. For example, 10.66 would be rounded to 10.7.
If we want to round a number, and the next digit is lower that 5, we just maintain the same digit. For example, 10.44 would be rounded to 10.4
However, there's a specific case, if we want to round a number to the tenth, and the following digit is 5, we could round up or round down the tenth digit. If the digit we want to round is pair, then we maintain the same digit, if it's odd, we can round to the upper digit. For example, 10.65 would be rounded to 10.6, and 10.75 would be rounded to 10.8
Therefore, according to these rules, the round number would be $3.8 and $3.8
Monday's gas, $3.80 rounded to the nearest tenth of a dollar would be $3.80 (its already there) Tuesday' gas, $3.85 rounded to the nearest tenth of a dollar would be $3.90 Hope this helps!! and if you ever need anything else just ask! :)
The population average is a descriptive statistic. It informs about how the population looks like, in this case, the population looks like having a average of 1000.
If, using her class's average where to infer the population average that is inferential statistic. But that is not the case