In order to determine whether or not there is a significant difference between the hourly wages of two companies, the following data have been accumulated.
company 1 company 2 n1 = 80 n2 = 60 xì„1 = $10.80 xì„2 = $10.00 ïƒ1 = $2.00 ïƒ2 = $1.50 refer to exhibit 10-13. the point estimate of the difference between the means (company 1 – company 2) is

a. 8
b. –20
c. 50
d. 20