While studying the effect of radiation on octopus intelligence, you uncover some interesting data. Your hypothesis is that octopuses will be smarter if they are exposed to higher radiation levels as babies. In the experiment, 26 baby octopuses (all females of the same species, housed in identical aquaria, same ages, fed the same food) were randomly divided into six groups, which were exposed to different levels of radiation in their seawater for four weeks. Five additional octopuses were raised without radiation as a control (radiation level 0). Later, at 1 year old, each octopus was given an identical puzzle jar to open.

(2 points) Make a scatterplot of time to open vs. radiation level from these data. Make sure the graph is properly labeled and titled. Then submit that graph along with answers to the questions on the next page. There are two possible approaches: You could graph the average time-to-open for the octopuses in each radiation group (in which case you must include error bars for that average), or you could graph each octopus separately (in which case you would not include any error bars).

Octopus	Radiation Level	Time to open Puzzel jar (s)
Cath-2	0	115
Cersei	0	100
Calistria	0	103
Casandalee	0	96
Coraline	0	98
Anyanwu	1	120
Baruch	1	95
Celeborn	1	90
Doctor	1	100
Eowyn	2	85
Faramir	2	100
Gamgee	2	75
Hiro	2	70
Ilia	3	75
Jondalar	3	64
Kvothe	3	66
Lyra	3	80
Magneto	4	58
Nyssa	4	64
Olorin	4	70
Palicrovol	4	55
Quirrell	4	60
Roland	5	50
Sarah Jane	5	60
Teegan	5	62
Ulrich	5	52
Vaarsuvius	6	65
Will	6	51
Xavier	6	60
Y.T.	6	55
Zardoz	6	55

1. (2 points) What are the independent and dependent variables in this experiment?

2. (2 points) Does exposure to radiation seem to be associated with an increase in intelligence? (NOTE: Would more intelligence be associated with higher or lower time needed to open the jar?) What is the Rsquared value (the square of the correlation coefficient) for the overall correlation? Make sure to calculate it using the same data you used for your graph.

3. (2 points) Which of the radiation levels provided a significant increase in intelligence compared to the control group (the ones with zero radiation)? Provide p-values for each comparison.

4. (2 points) You want to breed octopuses which are as smart as possible but with no more radiation exposure than necessary. Which radiation level would you choose? Explain why you chose that level. As a place to start, consider which groups showed an effect of radiation compared to control. Then, determine whether there is reason to think that each radiation level produces a benefit compared to others.