<prompt> Average Mental IQ according to Wechslers Scale is -70-7980-8990-190110-119  <response>: Ans. is c i.e., 90-109 o Wechsler Adult Intelligence Scale WAIS David Wechsler 1939, published the first intelligence test designed for an adult population; It was the first IQ test based on NormalGaussian distribution. o It is currently in its fouh edition WAIS-1V. The original WAIS Form I was published in February 1955, as a revision of the Wechsler - Bellevue intelligence scale that had been released in 1939. Fouh edition WAIS-1V was released in 2008 by Pearson. o The median full scale IQ is Centered at 100, with a standard detion of 15. In a normal distribution, the IQ range of one SD above and below the mean i.e. 85 and 115 is where approximately 68 of all adult would fall. 