Snapper (Pagrus auratus) are a fish that is heavily targeted by recreational fishers in the Hauraki...

 

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Snapper (Pagrus auratus) are a fish that is heavily targeted by recreational fishers in the Hauraki Gulf. The legal minimum landed size is 30cm, and all snapper less than this size must be discarded (i.e., returned to the sea). An experiment was undertaken to determine the survival of discarded snapper. Snapper were caught by hook and line, measured for length, the hook was removed, and all snapper were placed in holding tanks for 5 days. The handling time (the duration between the fish being brought to the surface and being placed in a tank) was recorded as whether or not it was 2 minutes or less. It is of interest to learn about the survival probability of discarded snapper. In particular: o It is of interest to learn how fish length and handling time affect survival and quantify any significant effects. Did any effect of the length of the fish on the survival time depend on the handling time? We also want to estimate the probability of a 25 cm long snapper surviving for both handling times of 2 minute or less and for more than 2 minutes. o o The data set SnapSurv.csv contains the following variables: Surv Len Time Whether or not the snapper survived, coded as 1-alive after 5 days, 0-dead. The length of the snapper (cm). The amount of time the snapper was handled (classified as either Less if 2 minutes or less, or More if more than 2 minutes). Comment on the plot of the data. Fit a logistic regression model. Determine whether the model can be simplified and determine an appropriate final model. Estimate the survival probability of a 25 cm snapper for with handling times of both "Less" and "More". (You do not need interval estimates.) Write a method and Assumption Checks section. • Write an Executive Summary. Remember to answer all questions of interest. Snapper (Pagrus auratus) are a fish that is heavily targeted by recreational fishers in the Hauraki Gulf. The legal minimum landed size is 30cm, and all snapper less than this size must be discarded (i.e., returned to the sea). An experiment was undertaken to determine the survival of discarded snapper. Snapper were caught by hook and line, measured for length, the hook was removed, and all snapper were placed in holding tanks for 5 days. The handling time (the duration between the fish being brought to the surface and being placed in a tank) was recorded as whether or not it was 2 minutes or less. It is of interest to learn about the survival probability of discarded snapper. In particular: o It is of interest to learn how fish length and handling time affect survival and quantify any significant effects. Did any effect of the length of the fish on the survival time depend on the handling time? We also want to estimate the probability of a 25 cm long snapper surviving for both handling times of 2 minute or less and for more than 2 minutes. o o The data set SnapSurv.csv contains the following variables: Surv Len Time Whether or not the snapper survived, coded as 1-alive after 5 days, 0-dead. The length of the snapper (cm). The amount of time the snapper was handled (classified as either Less if 2 minutes or less, or More if more than 2 minutes). Comment on the plot of the data. Fit a logistic regression model. Determine whether the model can be simplified and determine an appropriate final model. Estimate the survival probability of a 25 cm snapper for with handling times of both "Less" and "More". (You do not need interval estimates.) Write a method and Assumption Checks section. • Write an Executive Summary. Remember to answer all questions of interest.

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From the plot we can see that the survival rate of the snapper decreases as the length of the fish i... View the full answer