Determine whether the study depicts an observational study or an experiment. Seventh-grade students are randomly divided into two groups. One group is taught math using traditional techniques ; the other is taught math using a reform method. After 1 year, each group is given an achievement test to compare proficiency.

Seventh-grade students are randomly divided into two groups. One group is taught math using traditional techniques; the other is taught math using a reform method. After 1 year, each group is given an achievement test to compare proficiency. Determine whether the study depicts an observational study or an experiment.

Determine whether the sampling is dependent or independent. Indicate whether the response variable is qualitative or quantitative. An educator wants to determine whether a new curriculum significantly improves standardized test scores for third grade students. She randomly divides 80 third-graders into two groups. Group 1 is taught using the new curriculum, while group 2 is taught using the traditional curriculum. At the end of the school year, both groups are given the standardized test and the mean scores are compared.

Classify the variable as qualitative or quantitative. If the variable is quantitative, state whether it is discrete or continuous. Number of new automobiles sold at a dealership on a given day.

Determine whether the underlined value is a parameter or a statistic. Following the 2014 national midterm election. $\underline{\text{18\\%}}$ of the governors of the 50 United states were female.

Determine whether the underlined value is a parameter or a statistic. The average score for a class of 28 students taking a calculus midterm exam was $\underline{\text{72\\%}}$

What is a cross-sectional study? What is a case-control study? Which is the superior observational study? Why?

The logistic growth function

$$P ( x ) = \frac { 90 } { 1 + 271 e ^ { - 0.122 x } }$$

models the percentage, P(x), of Americans who are x years old with some coronary heart disease. Use the function to solve. What percentage of 80-year-olds have some coronary heart disease?

Is there an association between level of happiness and the risk of heart disease? Researchers studied 1739 people over a 10-year period and asked questions about their daily lives and the hassles they face. The researchers also determined which individuals in the study experienced any type of heart disease. After their analysis, they concluded that happy individuals are less likely to experience heart disease.

What type of observational study is this? Explain.

A simple random sample of size n is drawn. The sample mean, $\bar{x}$, is found to be 18.4, and the sample standard deviation, s, is found to be 4.5.

Construct a 95% confidence interval for $\mu$ if the sample size, n is 35.

A(n) ____ is a numerical summary of a sample.

How many different tests can be made from a test bank of 20 questions if the test consists of 5 questions?

Explain the difference between a population and a sample.

Determine whether the study depicts an observational study or a designed experiment. Identify the response variable in each case.

A pollster asks 800 adult Americans whether the gap between the rich and poor will grow or shrink over the next 30 years.