For a table of national information regarding a specific country, the sample correlation coefficients with Internet use are as follows: 0.545 for GDP, 0.734 for cellular phone use, 0.664 for literacy, -0.893 for fertility, and 0.854 for CO2 emissions. Suppose we fit a linear model to predict GDP, cellular phone use, literacy, fertility, and CO2 emissions using Internet use as the explanatory variable.  Among these variables, the largest percent of data variability in ______  is explained by the linear model using Internet use as the explanatory variable. Fill in the blank.

A 95% confidence interval for the mean body temperature (in °F) was computed as (98.1, 98.4), based on body temperatures from a sample.  If we were to construct a 98% confidence interval instead, which of the following intervals would be plausible?  

A psychologist is investigating whether there is an association between individuals’ preferred music genres (e.g., hip hop, classical, pop, jazz, country, etc.) and their age groups (under 20, 20-29, 30-39, 40-49, 50 and over 50). Which type of graph is most appropriate for visualizing the distribution of favorite music genres across different age groups and evaluating their association?

Eli wants to determine whether or not there is an association between gender and GPA among high school seniors in Ohio. He randomly selects 100 high school seniors at Amelia High School, a public school in southwest Ohio. He asks them to report their gender, as well as their current GPA. Out of these 100 students, 57 were female and 43 were male. The average GPA of the 57 female high school seniors was 3.4  What is the sample in this study?

Four separate random samples (of four completely different populations) were taken.  We graphed all four side-by-side in two different ways below.  Which of the following statements is correct?

A class of n = 80 students had scores on quiz as graphed below. Which of the following statement s is incorrect? A. B.

You may find your exam booklet here:  Midterm2_Su2025.pdf

Suppose you want to study job satisfaction among hospital nurses in a particular city that has 20 hospitals. You randomly select only one of these hospitals and then interview 20 nurses from that hospital about their job satisfaction. What sampling method is used here?  Is this sample likely to be representative of the population?

In a study that investigates the impact of the Danish Action Plan for the Aquatic Environment, which addresses pollution of the Danish water resources, the concentration of nitrogen (measured in g/m3) was measured in a particular river in 1998, 2003, 2011, and 2020. Six measurements were randomly taken in each year. A summary of the nitrogen concentration is provided. We want to evaluate the relationship between the two variables using an ANOVA at the 5% significance level.  In order to say about the p-value, which of the following information will be used? Source DF Sum Sq Mean Sq F value p-value Year 7.39 3.695 13.52 Residuals 4.1 0.2733 Total 23 11.49

In the past 10 years, the share of US adults living without a partner/spouse has increased. A recent study collects a random sample of 12,500 adults, and reports with 95% confidence that between 59.36% and 60.84% of US adults live without a partner/spouse.  Which is the margin of error? Leave it as a percentage.