A clinical trial tests a method designed to increase the probability of conceiving a girl. In the study 320 babies were​ born, and 256 of them were girls. Use the sample data to construct a 99​% confidence interval estimate of the percentage of girls born. Based on the​ result, does the method appear to be​ effective?

One year’s survey results, of 1525 respondents, 846 said that they expected difficulty finding a job.  Find a 95% confidence interval for the population proportion of students who expect difficulty finding a job.

Among 1815 randomly selected high school students surveyed by the Centers for Diseases Control, 300 said they were current smokers. d. Interpret the 95% confidence interval in this context.

A clinical trial tests a method designed to increase the probability of conceiving a girl. In the study 690 babies were​ born, and 345 of them were girls. Use the sample data to construct a 99​% confidence interval estimate of the percentage of girls born. Based on the​ result, does the method appear to be​ effective?

A clinical trial tests a method designed to increase the probability of conceiving a girl. In the study 360 babies were​ born, and 324 of them were girls. Use the sample data to construct a 99​% confidence interval estimate of the percentage of girls born. Based on the​ result, does the method appear to be​ effective?

In a science fair​ project, Emily conducted an experiment in which she tested professional touch therapists to see if they could sense her energy field. She flipped a coin to select either her right hand or her left​ hand, and then she asked the therapists to identify the selected hand by placing their hand just under​ Emily's hand without seeing it and without touching it. Among 337 trials, the touch therapists were correct 163 times.  Using​ Emily's sample​ results, construct a 95​% confidence interval estimate of the proportion of correct responses made by touch therapists. (round to 3 decimal places)

A statistics student wants to conduct a study to determine the proportion of workers in Cititon who commute to another town for work. If the student wants a 90% confidence interval with a margin of error of 2%, how many workers should be in her sample?