Charles Kline monitors the daily performance of his investment portfolio by recording a "+" or a "-"sign to indicate whether the portfolio's value increased or decreased from the previous day.His record for the last eighteen business days is "- + + - - - + - - + + + - + + + + -".The number of runs in this sample is ___.
A)uncertain
B)four
C)five
D)nine
E)one

Question

Quizplus · Accepted Answer

A run is defined as a series of consecutive observations with the same sign. From the given record, we have the following runs:

- (-)
- (+)
- (+)
- (-)
- (-)
- (-)
- (+)
- (-)
- (-)
- (+)
- (+)
- (+)
- (-)
- (+)
- (+)
- (+)
- (+)
- (-)

There are a total of 9 runs in this sample. Therefore, the answer is (D) nine.

Charles Kline Monitors the Daily Performance of His Investment Portfolio