The agencies, however, are not concerned with statistical significance. The agencies would like to know if the difference in speed is of practical importance to them. Market research has shown that in order to justify the higher price of color displays, they must be faster by an average of at least 10 seconds per transaction. 4. Construct a 90% confidence interval for the difference in the means (color minus black and white). 5. Use the interval to explain to the agencies if they should or should not pay for color displays. Use complete sentences and proper grammar.