This question is incomplete, the complete question is;
In a survey, 55% of the voters support a particular referendum. If 40 voters are chosen at random,
find the mean and variance for the number of voters who support the referendum.
Answer:
a) The Mean is 22
b) Variance is 9.9
Explanation:
Given that;
55% of the voters support a particular referendum p = 0.55
q = 1 - p = 1 - 0.55 = 0.45
sample size n = 40
a)
Mean = sample size n × p
Mean = 40 × 0.55
Mean = 22
Therefore the Mean is 22
b)
Variance = n × p × q
so we substitute
Variance = 40 × 0.55 × 0.45
Variance = 9.9
Therefore the Variance is 9.9