Question

1. Using R Programing
2. Conduct an experiment in the lab to assess the response of the gonadosomatic index (GSI) in female Mirogrex canadensis (a sardine) to different combinations of temperature (16C or 27C) and photoperiod (9 hours or 14 hours). GSI is the ratio of gonad to non-gonad weight so the GSI measures the development of ovaries. The concept here is that you will be able to determine if the fish responds to photoperiod differences similarly or differently at typical winter and summer temperatures.
   1. They suggest to you that you only need 4 aquaria – one for each combination of temperature and photoperiod in which you can place 5 replicate fish. You say no. Why?
   2. They relent and you now have 20 aquaria for your 20 fish. You assign fish and treatment combinations randomly and run your experiment.
      1. What kind of experiment is this?
      2. Analyze the data and report your results.

Temp	photoperiod	GSI
27C	09h	0.9
27C	09h	1.06
27C	09h	0.98
27C	09h	1.29
27C	09h	1.12
16C	09h	2.31
16C	09h	2.88
16C	09h	2.42
16C	09h	2.66
16C	09h	2.94
27C	14h	0.83
27C	14h	0.67
27C	14h	0.57
27C	14h	0.47
27C	14h	0.66
16C	14h	1.01
16C	14h	1.52
16C	14h	1.02
16C	14h	1.32
16C	14h	1.63

Answer 1

1. hey suggest to you that you only need 4 aquaria – one for each combination of temperature and photoperiod in which you can place 5 replicate fish. You say no. Why?

Because there is only 2 replication per group.

1. They relent and you now have 20 aquaria for your 20 fish. You assign fish and treatment combinations randomly and run your experiment.
   1. What kind of experiment is this?

Two-Way ANOVA with replication

1. Analyze the data and report your results.

Analysis of Variance

Source	DF	Adj SS	Adj MS	F-Value	P-Value
Temp	1	6.2273	6.22728	126.98	0.000
photoperiod	1	3.9250	3.92498	80.03	0.000
Temp*photoperiod	1	1.0397	1.03968	21.20	0.000
Error	16	0.7847	0.04904
Total	19	11.9766

There is a main effect of Temp.

There is a main effect of photoperiod.

There is an interaction effect.