Suppose the true population proportion werep= 0.5 and a researcher takes asimple random sample of sizen= 50.
(a) Find and interpret the standard deviation of the sample proportion ˆp.
(b) Calculate the probability that the sample proportion will be larger than 0.55 for a random sample ofsize 50.

Respuesta :

Answer:

answer is almost 0 i.e impossible event.

Step-by-step explanation:

given that the  the true population proportion were

p= 0.5

a) Std deviation of sample proportion = [tex]\sqrt{\frac{pq}{n} } \\=0.0707[/tex]

This is the std deviation for a single trial.  We know in binomial variance is npq.  Using this we can say for a single trial, variance would be pq/n and hence std deviation of proportion is square root of pq/n

b) The probability that the sample proportion will be larger than 0.55 for a random sample ofsize 50

= P(p>0.55)

= [tex]P(Z>\frac{0.05}{0.0707} )\\= P(Z>7.07)\\<0.00001[/tex]