Question

A random sample of 900 individuals has been selected from a large population. It was found that 180 are regular users of vitamins. Thus, the proportion of the regular users of vitamins in the population is estimated to be 0.20. The standard error of this estimate is approximately: a) 0.1600 b) 0.0002 c) 0.4000 d) 0.0133 e) 0.0267 E A traffic consultant wants to estimate the proportion of cars on a certain street that have more than two occupants. She stands at the side of the road for two hours on a weekday afternoon and flips a coin each time a car approaches. If the coin comes up heads, she counts the number of occupants in the car. After two hours, she has counted 103 cars, 15 of which had more than two occupants. Which condition for constructing a confidence interval for a proportion has she failed to satisfy

Answer 1

Answer:

Question 1: The most correct option is option D, which is 0.0133

Question 2: Her data is a random sample from the population of interest.

Explanation: For the first question;

Standard error I the error in the standard deviation. To calculate standard error the formula is used.

S.E = Sd/√n

S.E = standard error

Sd= standard deviation = 0.2

n = number of occurrence = 180

The proportion of the regular users of vitamin among the 180 people is the standard deviation between them.

Using equation above.

S.E = 0.20 ÷ √180 =

0.20 ÷ 13.42 = 0.0149

S.E is 0.0149, when compared to the options, the most correct option is 0.0133, because the question states the answer to be approximately to which of the option.

QUESTION2:

Her research will have much error, because she chooses the car to count. Therefore the research procedure has not satisfied the process that will produce an accurate result. Since she has choosed the street to be her population of interest, all the cars in the street should be counted.

This is not a randomized controlled research, so selection of cars to count is not necessary.