A study was conducted at the Department of Health and Physical Education at Virginia Polytechnic Institute and State University to determine if 8 weeks of training truly reduces the cholesterol levels of the participants. A treatment group consisting of 15 people was given lectures twice a week on how to reduce their cholesterol level. Another group of 18 people of similar age were randomly selected as a control group. All participants' cholesterol levels were recorded at the end of the 8-week program and are listed below.
Treatment: 129 131 154 172 115 126 175 191 122 238 159 156 176 175 126
Control: 151 132 196 195 188 198 187 168 115 165 137 208 133 217 191 193 140 146
Can we conclude, at the 5% level of significance, that the average cholesterol level has been reduced due to the program? Make the appropriate test on means.