28. Presidential Election Winners. Since 1852, every U.S. presidential election has been won by either the Democratic Party or the Republican Party. The following sequence represents the presidential election winners since 1852, with D representing Democrat and R representing Republican.18 Test whether the sequence is random, using level of significance .
| D | D | R | R | R | R | R | R | D | R | D | R | R | R | R | D | D | R | R | R | D |
| D | D | D | D | D | R | R | D | D | R | R | D | R | R | R | D | D | R | R | D | D |