A random sample of 15 people was selected to take an Intelligence Test. After each person completed the test, they were assigned an intelligence quotient (IQ) based on their performance on the test. The resulting 15 IQs are sorted as follows:

75 78 83 85 85 96 96 96 97 97 116 117 122 123 128

i)Determine the mean IQ

ii)Determine the standard deviation of the IQ

iii)Calculate the inter-quartile range