Your business has conducted four market research surveys in the past year. The cost per survey is as follows: Survey $900, Survey 2: $1,200, Survey 3: $1,500, Survey 4: $1,700. What is the average cost of the market research surveys?

O a) $1,000
b) $1,092
c) $1,325
O d) $1,920

The distribution of the amount of money spent by students for textbooks in a semester is approximately normal in shape with a mean of $235 and a standard deviation of $20. according to the standard deviation rule, how much did almost all (99.7%) of the students spend on textbooks in a semester?