People in the aerospace industry conducted a pilot study to determine the relationship between the weight and cost of a major object being sent into space. The results of the pilot study are contained in datafile SP13.53, contained in a folder under the CML Quizzes tab. Determine the number of observations needed to be 86% confident thatthe estimate of the averagecost is within$18 of the overall mean cost. Note: Assume that the pilot study standard deviation is a good estimate of the population standard deviation, that an appropriate value from the Z-table can be used, and that hand calculations are used to find the answer (i.e. do not use Kaddstat).Hint:in Excel, use Data > DAta Analysis > Descriptive Statistics, to find the sample standard deviation.