CITA confident over dolphin survey

CITA is confident the results of the recent survey of its membership on the establishment of captive dolphin parks in the Cayman Islands reflect an accurate assessment of the membership’s point of view as reported by the respondents.

The CITA issued a press release this week in response to recent questions on the methodology of the recently released survey.

According to the press release, for the survey, the following results were obtained using the generally accepted confidence level of 95 per cent.

It says that the percentage of all members voting against the introduction of captive dolphin theme parks in the Cayman Islands is 74 per cent, plus or minus eight per cent.

The percentage of all members voting for the introduction of captive dolphin theme parks in the Cayman Islands is 13 per cent plus or minus six per cent.

‘CITA used an independent survey tool (Zoomerang) to survey its membership on their views regarding the establishment of captive dolphin facilities in the Cayman Islands.

‘One key issue about the survey has been the statistical significance of the information gathered. In other words, how representative of the membership’s perspective is the data that was collected?’

The release points out that it is important to understand a number of terms when looking at statistical significance.

Stats explained

The following information regarding statistical significance comes from the website for Creative Research Systems (http://www.surveysystem.com/sscalc.htm).

‘The confidence interval is the plus-or-minus figure usually reported in newspaper or television opinion poll results. For example, if you use a confidence interval of four and 47 per cent of your sample picks an answer you can be ‘sure’ that if you had asked the question of the entire relevant population between 43 per cent (47-4) and 51 per cent (47+4) would have picked that answer.

‘The confidence level tells you how sure you can be. It is expressed as a percentage and represents how often the true percentage of the population who would pick an answer lies within the confidence interval. The 95 per cent confidence level means you can be 95 per cent certain. Most researchers use the 95 per cent confidence level.

‘When you put the confidence level and the confidence interval together, you can say that you are 95 per cent sure that the true percentage of the population that would have picked that answer is between 43 per cent and 51 per cent.

‘Your accuracy also depends on the percentage of your sample that picks a particular answer. If 99 per cent of your sample said ‘Yes’ and one per cent said ‘No’ the chances of error are remote, irrespective of sample size. However, if the percentages are 51 per cent and 49 per cent the chances of error are much greater.’

The release also notes that the larger your sample, the more sure you can be that their answers truly reflect the population. This indicates that for a given confidence level, the larger your sample size, the smaller your confidence interval. However, the relationship is not linear (i.e., doubling the sample size does not halve the confidence interval).

Sample size

The CITA survey had a sample size of 61, of which 74 per cent voted against the introduction of captive dolphin theme parks in the Cayman Islands.

This yielded a confidence interval of 8 per cent at a 95 per cent confidence level. Thus, when you put the confidence level and the confidence interval together, CITA can say that they are 95 per cent sure that the true percentage of the membership that would have voted against the introduction of captive dolphin theme parks in the Cayman Islands is between 66 per cent and 82 per cent. Only 13 per cent were in favour of the parks, yielding a confidence interval of six per cent at a 95 per cent confidence level.

‘Thus, CITA can say that they are 95 per cent sure that the true percentage of the membership that would vote for the introduction of captive dolphin theme parks in the Cayman Islands is between seven per cent and 19 per cent.’

Therefore, the press release concludes, CITA is confident that the results reflect an accurate assessment of the membership’s point of view as reported by the respondents.

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