Question 1

The population proportion of voters in favour of a particular political candidate is being estimated with a confidence interval. A random sample of 55 voters is taken, and 28 are found to be in favour. Find and interpret a 90% confidence interval for the population proportion of people in favour of this political candidate.

Accepted Answer

The answer of The population proportion of voters in favour...

Question 2

What is the width of a 99% confidence interval for the population proportion of people that own more than one mobile phone, if a random sample of 50 people was taken, and 10 of these had more than one mobile phone?

Accepted Answer

The answer of What is the width of a 99%...

Question 3

The head of the statistics department in a certain university believes that 70% of the department's graduate assistantships are given to international students. A random sample of 50 graduate assistants is taken.
a. Assume that the chairman is correct and p = 0.70. What is the sampling distribution of the sample proportion $\hat { p }$ . Explain.
b. Find the expected value and the standard error of the sampling distribution of $\hat { p }$ .
c. What is the probability that the sample proportion $\hat { p }$ will be between 0.65 and 0.73?
d. What is the probability that the sample proportion $\hat { p }$ will be within ±0.05 of the population proportion p?

Accepted Answer

The answer of The head of the statistics department in...

Question 4

A politician believes that the proportion of voters who will vote for a Coalition candidate in the 2004 general election is 0.65. A sample of 500 voters is selected at random.
a. Assume that the politician is correct and p = 0.65. What is the sampling distribution of the sample proportion $\hat { p }$ ? Explain.
b. Find the expected value and standard deviation of the sample proportion $\hat { p }$ .
c. What is the probability that the number of voters in the sample who will vote for a Labor candidate in the 2004 general election will be between 340 and 350?

Accepted Answer

The answer of A politician believes that the proportion of...

Question 5

A simple random sample of 100 observations is taken from a population. Assume that the population proportion p = 0.5.
a. What is the expected value of the sample proportion $\hat { p }$ ?
b. What is the standard error of the sample proportion $\hat { p }$ ?

Accepted Answer

The answer of A simple random sample of 100 observations...

Question 6

Determine the minimum sample size required for estimating the population proportion of number of people who drive to work, to within 0.003, with 80% confidence.

Accepted Answer

The answer of Determine the minimum sample size required for...

Question 7

What is the margin of error for a 99% confidence interval for the population proportion of people that own more than one mobile phone, if a random sample of 50 people was taken, and 10 of these had more than one mobile phone?

Accepted Answer

The answer of What is the margin of error for...

Quiz 11: Estimation: Describing a Single Population

What is the width of a 99% confidence interval for the population proportion of people that own more than one mobile phone, if a random sample of 50 people was taken, and 10 of these had more than one mobile phone?

A simple random sample of 100 observations is taken from a population. Assume that the population proportion p = 0.5. a. What is the expected value of the sample proportion p^\hat { p }p^​ ? b. What is the standard error of the sample proportion p^\hat { p }p^​ ?

Determine the minimum sample size required for estimating the population proportion of number of people who drive to work, to within 0.003, with 80% confidence.

What is the margin of error for a 99% confidence interval for the population proportion of people that own more than one mobile phone, if a random sample of 50 people was taken, and 10 of these had more than one mobile phone?

A simple random sample of 100 observations is taken from a population. Assume that the population proportion p = 0.5. a. What is the expected value of the sample proportion $\hat { p }$ ? b. What is the standard error of the sample proportion $\hat { p }$ ?