Question

1) The Law School Admission Test (LSAT) is an examination for prospective law school students. Scores on the LSAT are known to have a normal distribution and a population standard deviation of σ = 10. A random sample of 250 LSAT takers produced a sample mean of 502.

What value should be used for the confidence multiplier in a 99% confidence interval for the population mean LSAT score?

Group of answer choices

1.960

2.0

2.576

1.645

2) A large supermarket chain wanted to estimate the population mean number of items purchased by customers per visit. A random sample of 144 customers was chosen and it was found that the sample mean number of items purchased was 24.3. The sample standard deviation was 3.0 items.

Compute a 95% confidence interval for μ, the population mean number of items purchased by customers per visit. Note that because the sample size is sufficiently large, you can use a z* confidence multiplier instead of a t* confidence multiplier. You should use the following formula:

In the blank below, enter the lower bound of the 95% confidence interval for μ. For example, if your confidence interval is (22.115, 25.876), the lower bound would be 22.115. Round your answer to two decimal places.

3) A large supermarket chain wanted to estimate the population mean number of items purchased by customers per visit. A random sample of 144 customers was chosen and it was found that the sample mean number of items purchased was 24.3. The sample standard deviation was 3.0 items.

Compute a 95% confidence interval for μ, the population mean number of items purchased by customers per visit. Note that because the sample size is sufficiently large, you can use a z* confidence multiplier instead of a t* confidence multiplier. You should use the following formula:

In the blank below, enter the upper bound of the 95% confidence interval for μ. For example, if your confidence interval is (22.115, 25.876), the upper bound would be 25.876. Round your answer to two decimal places.

4) A large supermarket chain wanted to estimate the population mean number of items purchased by customers per visit. A random sample of 144 customers was chosen and it was found that the sample mean number of items purchased was 24.3. The sample standard deviation was 3.0 items.

Compute a 99% confidence interval for μ, the population mean number of items purchased by customers per visit. Note that because the sample size is sufficiently large, you can use a z* confidence multiplier instead of a t* confidence multiplier. So you should use the following formula:

In the blank below, enter the upper bound of the 99% confidence interval for μ. For example, if your confidence interval is (22.115, 25.876), the upper bound would be 25.876. Round your answer to three decimal places.

Answer 1