Population Parameter

Which of the following answers is CORRECT for constructing a 98% confidence interval for a difference between two population proportions?

Suppose a 95% confidence interval for \mu_1-\mu_2 is (-2.13,1.48), what can you conclude?

• We are 95% confident that there is no difference between the population means.

• We are 95% confident that there is a difference between the population means.

Is there any difference between population variances at 99% level of confidence if the 99% confidence interval (CI) for the ratio of population variance is (0.78, 1.56)? Verify.

• No difference because the 99% CI contains 1.

• Yes, there is a difference because the 99% CI does not contain 0.

• No difference because the upper limit of 99% CI is greater than the lower limit.

A school principal wants to see which subject the 845 students in his school liked best.
Which choice best represents a parameter?

• 700 of the 845 students prefer math.

• 100 of the 120 students surveyed prefer math.

• 845 students

• 120 students surveyed

These symbols represent the mean and standard deviation for which of the following distributions?

• The Population

• The Sample

• The Sampling Distribution

Which of the following choices is CORRECT for a 99% confidence interval for a population proportion when the sample size is large?

A sample of 400 racing cars showed that 80 cars cost over $700,000. What is the 99% confidence interval of the true proportion of cars costing over $700,000?

• 0.001 < p < 0.005

• 0.566 < p < 0.693

• 0.148 < p < 0.252

• 0.023 < p < 0.045

A survey of 800 women shoppers found that 17% of them shop on impulse.  What is the 98% confidence interval for the true proportion of women shoppers who shop on impulse? 

• 0.148 < p < 0.192

• 0.136 < p < 0.204

• 0.144 < p < 0.196

• 0.139 < p < 0.201

In a survey of 104 students, it was found that 79 went to the homecoming game this year. Calculate a 99% confidence interval for p.

• (0.652, 0.868)

• (0.691, 0.829)

• (0.678, 0.842(

• (0.685, 0.895)

In a survey of 104 students, it was found that 79 went to the homecoming game this year. A 99% confidence interval for p is (0.652, 0.868). Interpret this interval.

• 99% of the time the true proportion of people who went to the homecoming game this year is between 65.2% and 86.6%.

• The probability that the population proportion of people who went to the homecoming game this year is between 65.2% and 86.6% is 95%.

• Based on this sample, I am 99% confident that the true proportion of people who went to the homecoming game this year is between 65.2% and 86.6%.

• 99% of all possible intervals calculated this way will capture the true proportion of people who went to the homecoming game this year