To name a line segment, we use two letters of the endpoints in any order with a horizontal line above them. Hence, we can name the segment as:
__ __
\(\displaystyle{J}{K}{\quad\text{or}\quad}{K}{J}\)

Question

asked 2020-12-03

The article “Rocker Shoe Put to the Test: Can it Really Walk the Walk as a Way to Get in Shape?” (USA TODAY, October 12, 2009) describes claims made by Skechers about Shape-Ups, a shoe line introduced in 2009. These curved-sole sneakers are supposed to help you “get into shape without going to the gym” according to a Skechers advertisement. Briefly describe how you might design a study to investigate this claim. Include how you would select subjects and what variables you would measure. Is the study you designed an observational study or an
experiment?

asked 2021-03-02

In the 1970s a study was conducted in Philadelphia in which 500 cases were randomly assigned to treatments for the common cold: 250 subjects received the medication and 250 received a placebo. A total of 383 patients improved within 24 hours. Of those who received the medication 241 improved within 24 hours and of those who received the placebo 142 improved within 24 hours. A test of significance was conducted on the following hypotheses.

\(\displaystyle{H}_{{o}}\): The rates for the two treatments are equal.

\(\displaystyle{H}_{{a}}\): The treatment of medication has a higher improvement rate.

This test resulted in a p-value of 0.0761.

a.) Interpret what this p-value measures in the context of this study.

b.) Based on this p-value and study design, what conclusion should be drawn in the context of this study? Use a significance level of \(\displaystyle\alpha={0.05}\).

c.) Based on your conclusion in part (b), which type of error, Type I or Type II, could have been made? What is one potential consequence of this error?

\(\displaystyle{H}_{{o}}\): The rates for the two treatments are equal.

\(\displaystyle{H}_{{a}}\): The treatment of medication has a higher improvement rate.

This test resulted in a p-value of 0.0761.

a.) Interpret what this p-value measures in the context of this study.

b.) Based on this p-value and study design, what conclusion should be drawn in the context of this study? Use a significance level of \(\displaystyle\alpha={0.05}\).

c.) Based on your conclusion in part (b), which type of error, Type I or Type II, could have been made? What is one potential consequence of this error?

asked 2021-03-09

A proposed study design is to leave 100 questionnaires by the checkout line in a student cafeteria. The questionnaire can be picked up by any student and returned to the cashier. Explain why this volunteer sample is a poor study design.

asked 2021-02-12

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.

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.

asked 2020-12-15

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.

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.

asked 2020-11-29

State whether the investigation in question is an observational study or a designed experiment. Justify your answer in each case.

The Salk Vaccine. In the 1940s and early 1950s, the public was greatly concerned about polio. In an attempt to prevent this disease, Jonas Salk of the University of Pittsburgh developed a polio vaccine. In a test of the vaccine’s efficacy, involving nearly 2 million grade-school children, half of the children received the Salk vaccine, the other half received a placebo, in this case an injection of salt dissolved in water. Neither the children nor the doctors performing the diagnoses knew which children belonged to which group, but an evaluation center did. The center found that the incidence of polio was far less among the children inoculated with the Salk vaccine. From that information, the researchers concluded that the vaccine would be effective in preventing polio for all U.S. school children, consequently, it was made available for general use.

The Salk Vaccine. In the 1940s and early 1950s, the public was greatly concerned about polio. In an attempt to prevent this disease, Jonas Salk of the University of Pittsburgh developed a polio vaccine. In a test of the vaccine’s efficacy, involving nearly 2 million grade-school children, half of the children received the Salk vaccine, the other half received a placebo, in this case an injection of salt dissolved in water. Neither the children nor the doctors performing the diagnoses knew which children belonged to which group, but an evaluation center did. The center found that the incidence of polio was far less among the children inoculated with the Salk vaccine. From that information, the researchers concluded that the vaccine would be effective in preventing polio for all U.S. school children, consequently, it was made available for general use.

asked 2020-11-08

A researcher is conducting a study to examine the effects of cognitive behavior therapy for the treatment of social anxiety in a sample of 16 participants. He measures the social anxiety scores of participants before the tratment and then again after treatment and the resulting data is as follows:

n=16, M_0=5, s =4

a) What type of design is this study (single-sample, independent measures, repeated measures)

b)State the null and alternate hypotheses

c) Using an \(\displaystyle\alpha\le{v}{e}{l}{o}{f}{.05}{\left(\alpha={.05}\right)}\), identify the critical values of t for a 2-tailed test.

n=16, M_0=5, s =4

a) What type of design is this study (single-sample, independent measures, repeated measures)

b)State the null and alternate hypotheses

c) Using an \(\displaystyle\alpha\le{v}{e}{l}{o}{f}{.05}{\left(\alpha={.05}\right)}\), identify the critical values of t for a 2-tailed test.

asked 2021-02-19

Is wrapping a banana in plastic wrap and leaving the other bananas alone to see which one rots faster and experimental study design or and observational study design?

asked 2021-02-09

Know these terms. Explain in one sentence each what “randomized,” “double-blind,” and “placebo-controlled” mean in the description of the design of the study.

Experiment basics. Identify the subjects, the explanatory variable, and several response variables for this study.

Experiment basics. Identify the subjects, the explanatory variable, and several response variables for this study.

asked 2020-11-01

1.An investigator wants to assess whether the use of a specific medication given to infants born prematurely is associated with developmental delay. Infants who were born prematurely are recruited and followed for 2-years.

Some of the infants were given the medication at birth and others were not. All infants will undergo extensive testing at age 2 to assess various aspects of development.

What type of study design: The Case Report/Case Series, The Cross-Sectional Survey, The Cohort Study, The Case Control Study, The Nested Case-Control Study, The Randomized Controlled Trial or The Crossover Trial?

Some of the infants were given the medication at birth and others were not. All infants will undergo extensive testing at age 2 to assess various aspects of development.

What type of study design: The Case Report/Case Series, The Cross-Sectional Survey, The Cohort Study, The Case Control Study, The Nested Case-Control Study, The Randomized Controlled Trial or The Crossover Trial?