Study title

Data collection was performed for 63 randomly selected days during the periods from 3/2 to 15/6 and 6/8 to 15/12 2016. The selection of interview days was stratified to achieve a balance between the different days of the week, which means that the interviews were conducted on 9 over the year distributed Mondays, Tuesdays, Wednesdays, etc. The sample consisted of a simple random sample of individuals of the Swedish population aged between 9 and 79 years. The sample was drawn from the SPAR population register and included 16 990 persons living in Sweden. Non-response consisted of set of sampling units without a telephone number, wrong numbers, outside the target group and out of town during the whole period, etc.,and in the result a net sample of 12 057 people was achieved. Of these, interviews were conducted with 6 002 people. This means that the survey has a response rate of 50 percent. The proportion of pronounced refusals was 27 percent, while the remaining nonresponse is made up of those not reached, short-term sick, etc.

Probability