Complex numbers should be in the form ( a + bi ) where " a " and " b " need to have explicitly stated values .
For example : { 1 + 1i } is valid whereas { 1 + i } is not . { 0 + 9i } is valid whereas { 9i } is not .
In a survey , 55 % of the voters support a particular referendum . If 40 voters are chosen at random , and X is the number of voters that support this referendum , find the mean and variance of X . Place the mean in the first blank 21.5 and place the variance in the second blank . 9.0
13 .
Accepted characters : numbers , decimal point markers ( period or comma ), sign indicators ( - ), spaces ( e . g ., as thousands separator , 5 000 ), " E " or " e " ( used in scientific notation ). NOTE : For scientific notation , a period MUST be used as the decimal point marker .
Complex numbers should be in the form ( a + bi ) where " a " and " b " need to have explicitly stated values .
For example : { 1 + 1i } is valid whereas { 1 + i } is not . { 0 + 9i } is valid whereas { 9i } is not .
A DVD rental business determines that customers will rent X number of DVDs according to the following distribution :
Number
1 2 3 4 5 of DVDs rented X