My answers point wise are as follows.
1. The role of an estimator is to make estimations of various works like construction, manufacturing, service activity and so and so forth,
2, The duty of an estimator will be collecting the proposals, getting the specifications, getting any blueprint related to the work for which estimation is to be made. He should also obtain any other information that will be required or useful for him to make the estimation perfectly. He has to prepare the estimates as required. He has to evaluate the need for manpower, materials, and specialised manpower related to the area of work the time required for completion of the job, He has to see the accuracy of the information collected and try to gather the pricing information from the other competitors also. By talking all the inputs and their costs he has to make a presentation to the management on the cost he arrived with all detail. If there are any doubts or additional inputs from them the changes required are to be made and submit the proposal for approval.
3. An Engineering degree with or with or without experience or a diploma holder with some experience in the field is generally the criteria for a person to get selected to the post. For some industries, they may ask for Chartered Engineers. The expereince requirement will be different and the more the experience you have the higher the post you will get with higher pay packets.
4. Analyzing Information, Planning, Reporting Research Results, Strategic Planning, Attention to Detail, Mathematical Skills, team leading skills and some basic computer knowledge.
5. Estimation is very important for any type of work including manufacturing. A correct estimation will be useful in making a correct proposal and cost estimation. Based on these estimations only initial costing will be decided to understand the profitability of the business. While estimating the cost one should consider all aspects of the process including batch time, manpower, raw material, specification etc. If there is any change in the root also may affect the costing. SO casting plays a very important role in the industry.
6. The requirements for estimators vary from project to project, product to product and service to service. So the same person can't be competent to do estimation job in all fields The requirements will vary.
7. An estimator should know the calculation of a unit. What will be the cost per unit is generally what determines the minimum production capacity to make the process profitable. So he should be good at mathematics and some computer working also.
8. An estimator's job will be correct only when the work is completed his job as per the timing in his estimation and the project cost will be around what was estimated. So it is the duty of the estimator to see that the process if followed properly and work is completed on time with the exected level of quality.