Exam 10: Inference About Means and Proportions With Two Populations

Salary information regarding male and female employees of a large company is shown below. ​ If you are interested in testing whether or not the population average salary of males is significantly greater than that of females, the p-value is

Two major automobile manufacturers have produced compact cars with engines of the same size. We are interested in determining whether or not there is a significant difference in the mean MPG (miles per gallon) when testing for the fuel efficiency of these two brands of automobiles. A random sample of eight cars from each manufacturer is selected, and eight drivers are selected to drive each automobile for a specified distance. The following data (in miles per gallon) show the results of the test. Assume the population of differences is normally distributed. ​ At α = .10, the null hypothesis

The results of a recent poll on the preference of shoppers regarding two products are shown below. ​ At 95% confidence, the margin of error is

Salary information regarding male and female employees of a large company is shown below. ​ The point estimate of the difference between the means of the two populations is

The results of a recent poll on the preference of shoppers regarding two products are shown below. ​ The point estimate for the difference between the two population proportions in favor of this product is

In hypothesis tests about p₁ - p₂, the pooled estimator of p is a​(n)

The following information was obtained from matched samples taken from two populations. The daily production rates for a sample of workers before and after a training program are shown below. Assume the population of differences is normally distributed. ​ The null hypothesis to be tested is H₀: μd = 0. The test statistic is

Regarding inferences about the difference between two population means, the sampling design that uses a pooled sample variance in cases of equal population standard deviations is based on

If two independent large samples are taken from two populations, the sampling distribution of the difference between the two sample means

A statistics teacher wants to see if there is any difference in the abilities of students enrolled in statistics today and those enrolled five years ago. A sample of final examination scores from students enrolled today and from students enrolled five years ago was taken. You are given the following information. ​ What is the conclusion that can be reached about the difference in the average final examination scores between the two classes? (Use a .05 level of significance.)

The following information was obtained from matched samples taken from two populations. Assume the population of differences is normally distributed. ​ The 98% confidence interval for the difference between the two population means is

An insurance company selected samples of clients under 18 years of age and over 18 and recorded the number of accidents they had in the previous year. The results are shown below. ​ We are interested in determining if the accident proportions differ between the two age groups. Let p_u represent the proportion under and p_o the proportion over the age of 18. The null hypothesis is

A statistics teacher wants to see if there is any difference in the abilities of students enrolled in statistics today and those enrolled five years ago. A sample of final examination scores from students enrolled today and from students enrolled five years ago was taken. You are given the following information. ​ The test statistic for the difference between the two population means is

When developing an interval estimate for the difference between two population means with sample sizes of n₁ and n₂,

In order to determine whether or not there is a significant difference between the mean hourly wages paid by two companies (of the same industry), the following data have been accumulated. ​ The p-value is

The following information was obtained from matched samples taken from two populations. Assume the population of differences is normally distributed. ​ The null hypothesis tested is H₀: μd = 0. The test statistic for the difference between the two population means is

The results of a recent poll on the preference of shoppers regarding two products are shown below. ​ The 95% confidence interval estimate for the difference between the populations favoring the products is

The following information was obtained from independent random samples taken of two populations. Assume normally distributed populations with equal variances. ​ The degrees of freedom for the t distribution are

Generally, the ________ sample procedure for inferences about two population means provides better precision than the _______ sample approach.​

Salary information regarding male and female employees of a large company is shown below. ​ The standard error of the difference between the two sample means is