Average Mental IQ according to Wechsler's Scale is -

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 Normal/Gaussian 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.