Explain what is wrong with the study design. In a study to determine the factors that are associated with strong academic performance. 20 students are

The centers for Disease Control reported the percentage of people 18 years of age and older who smoke (CDC website, December 14, 2014). Suppose that a study designed to collect new data on smokers and Questions Navigation Menu preliminary estimate of the proportion who smoke of .26.
a) How large a sample should be taken to estimate the proportion of smokers in the population with a margin of error of .02?(to the nearest whole number) Use 95% confidence.
b) Assume that the study uses your sample size recommendation in part (a) and finds 520 smokers. What is the point estimate of the proportion of smokers in the population (to 4 decimals)?
c) What is the 95% confidence interval for the proportion of smokers in the population?(to 4 decimals)?

Many people believe that students gain weight as freshmen. Suppose we plan to conduct a study to see if this is true.
a) Describe a study design that would require a matched- pairs t procedure to analyze the results.
b) Describe a study design that would require a two- sample t procedure to analyze the results.

Whether the given study depicts an observational study or a designed experiment and to identify the response variable.
The study is conducted to compare the battery lives of a brand-name battery and a generic plain-label battery in digital cameras. For this purpose, 30 digital cameras are randomly selected and divided into 2 groups, one of the groups uses the brand-name battery while the other one uses the generic plain-label battery. In both the cameras, pictures are taken under identical conditions by keeping all variables, except the battery-type, in control.

Whether the given study depicts an observational study or an experiment.
The study involved 250 large-mouth bass in a lake. The 250 large-mouth bass were netted by conservation agents and were observed to determine how many of them were carrying parasites.

To state:The null and alternative hypotheses.
The sample of 223 sales executives are presented by sales scenarios. Each subject was assigned to the one of the five closing techniques. Sales executives wereasked about their level of trust in the 7-point scale.

What is the ideal study design from a statistical point of view?
-Clinical trial
-Observational studies
-A&B
-None of the above