The confidence interval is from 9.81 to 10.19.
We first find the mean of the data:
<span>(9.8+10.2+10.4+9.8+10.0+10.2+9.6)/7 = 10
Next we find the standard deviation:
</span>σ=√([<span>(9.8-10)^2+(10.2-10)^2+(10.4-10)^2+(9.8-10)^2+(10-10)^2+(10.2-10)^2+(9.6-10)^2]/7) = 0.262
The z-score for 95% confidence is found by
1-0.95 = 0.05; 0.05/2 = 0.025; from the z-table, it is 1.96.
The confidence interval is calculated using
</span>
<span>
</span>
The tree diagram shows that there are a total of six sample
spaces.
math------science
art
science---math
art---math
science
math---art
art---science
math
science---art
Based on the tree
diagram, the probability that the science project is first is two over six.
This is because science appears first in two out of the six sample spaces (boldened).