It has been reported that 63 of adults aged 65 and over got

It has been reported that 63% of adults aged 65 and over got their flu shots last year. In a random sample of 300 adults aged 65 and over, find the mean, variance, and standard deviation for the number who got their flu shots.

Solution

It has been reported that 63% of adults aged 65 and over got their flu shots last year. In a random sample of 300 adults aged 65 and over, find the mean, variance, and standard deviation for the number who got their flu shots.

Binomial distribution used.

n=300

p=0.63

Mean = Expectation = np = 189

Variance = np(1 - p)

= 300*0.63*0.37

= 69.93

Standard deviation = sqrt( 69.93) = 8.3624