Question

8.

A sample of 400 observations will be taken from an infinite population. The population proportion equals 0.8. The probability that the sample proportion will be greater than 0.83 is

Select one:

a. 0.4332

b. 0.0668

c. 0.9332

d. 0.5668

9.

Four hundred people were asked whether gun laws should be more stringent. Three hundred said "yes," and 100 said "no". The point estimate of the proportion in the population who will respond "yes" is

Select one:

a. 300

b. approximately 300

c. 0.75

d. 0.25

Answer 1

8)

Solution :

Given that,

p = 0.8

1 - p = 1 - 0.8 = 0.2

n = 400

= p = 0.8

=  p ( 1 - p ) / n

=   (0.8 * 0.2) / 400 = 0.02

= 0.02

P( > 0.83) = 1 - P( < 0.83)

= 1 - P(( - ) / < (0.83 - 0.8) / 0.02)

= 1 - P(z < 1.5)

= 1 - 0.9332

= 0.0668

Probability = 0.0668

b)

9)

Given that,

n = 400

x = 300

Point estimate = sample proportion = = x / n = 300 / 400 = 0.75

c)