I am trying to see how long a reading time my respondents had on a certain question, compared to if the respondent was pro or con gun-control (I have made an index describing the respondent's attitude towards gun-control). I have a variable (time_soren) which describes how long it took the respondent to read a statement and an index (gun_index) describing the respondent's attitude towards gun control. I now want to figure out if the respondent pro gun-control had a shorter reading time than a respondent con gun-control. But I can not figure out which command to use. To see if there is a statistically significant difference in reading time between respondents being pro vs. con gun control. Can anybody help?..