Question

making an inference
for two years, two samples of fish were taken from a pond. each year, the second sample was taken six months after the first sample.

year 1	sample 1	sample 2
catfish	9	9
bass	8	6
all fish	20	20

year 2	sample 1	sample 2
catfish	10	9
bass	2	1
all fish	20	20

make an inference about which fish increased its predicted average population from year 1 to year 2.

• all three types of fish increased their predicted average population.
• trout increased its predicted average population.
• bass increased its predicted average population.
• none of the fish increased their predicted average population.

Explanation:

Step1: Calculate Year1 avg per fish

Trout: $\frac{3+5}{2}=4$; Catfish: $\frac{9+9}{2}=9$; Bass: $\frac{8+6}{2}=7$

Step2: Calculate Year2 avg per fish

Trout: $\frac{8+10}{2}=9$; Catfish: $\frac{10+9}{2}=9.5$; Bass: $\frac{2+1}{2}=1.5$

Step3: Compare year-over-year averages

Trout: $9>4$ (increase); Catfish: $9.5>9$ (increase); Bass: $1.5<7$ (decrease)

Step4: Match to options

Only trout's increase is listed as a standalone correct option among choices.

Answer:

Trout increased its predicted average population.