Answer:
D
Step-by-step explanation:
First add all the simple line up so;

Then use Pythagoras to work out the lengths of the remaining lines

So to three decimal places it would be;

Answer:
20
Step-by-step explanation:
The answer would be 20 due to the fact that it would have to be 50 divided by 2.5 to get the answer of how many steps and 50 divided by 2.5 would equal 20
Basically degrees of freedom are related to sample size (n-1). If the df increases, it also stands that the sample size is increasing; the graph of the t-distribution will have skinnier tails, pushing the critical value towards the mean.