a) It is known that the standard deviation for a set of data is 2.4. Find the variance for the data. [1 mark]

b) If the lowest value in a set of data is 45, and the range for the same data is 12, find the highest value in the set. [1 mark]

c)Adult IQ scores have a bell-shaped distribution with a mean of 120 and a standard deviation of 20. Use the empirical rule to find the percentage of adults with IQ scores between 60 and 180. Include the % sign with your answer (leave no space between the number and the symbol of percentage).

d) Adult IQ scores have a bell-shaped distribution with a mean of 120 and a standard deviation of 20. What IQ score is positioned 1.8 standard deviations below the mean?