Juana is interested in estimating how long it takes students at her school to complete a maze she designed. She takes a random sample of   students and records how long it takes each of them to complete the maze. They work separately from each other, so Juana is willing to assume independence. Here are the data with summary statistics:Player     Time (minutes)     Mean   seconds Standard deviation   seconds Assume that all conditions for inference are met for this sample.Which of the following is a   confidence interval for the mean time (in seconds) it takes students to complete this maze?Choose 1 answer:Choose 1 answer:(Choice A)    A  (Choice B)    B  (Choice C)    C  (Choice D)    D (Choice E)    E

A simple random sample of seven (7) students is selected, and the students are asked how much time they spent studying for their University subjects (combined) outside class times. From past experience, it is known that these times (in hours) are distributed normally.The times (in hours) for the sample of students are as follows:2.3 7.2 4.5 12.5 6.6 2.5 5.5Based on these results, a confidence interval estimate for the population mean is found to be 5.9 ± 2.6.The level of confidence the researcher has used is closest to:-Group of answer choices95%90%97.5%99%

In which of the following scenarios can we calculate a confidence interval for the population mean? Check all that apply. A random sample of 60 cell phone calls is selected and the mean length of calls is determined to be 3.25 minutes with a standard deviation of 4.2 minutes. A random sample of 15 women athletes is selected and their mean weight is determined to be 136 pounds. Female athlete weights are known to be normally distributed with a population standard deviation of 20 pounds. A random sample of 14 cell phone calls is selected and the mean length of calls is determined to be 3.25 minutes with a standard deviation of 4.2 minutes. A random sample of 35 women athletes is selected and their mean weight is determined to be 136 pounds. Female athlete weights are known to be normally distributed with a population standard deviation of 20 pounds.

A random sample of 15 subjects was asked to perform a given task. The time in seconds it took each of them to complete the task is recorded below.37, 33, 28, 29, 37, 50, 28, 45, 49, 30, 39, 27, 40, 48, 26Send data to calculatorIf we assume that the completion times are normally distributed, find a 95% confidence interval for the true mean completion time for this task. Give the lower limit and upper limit of the 95% confidence interval.Carry your intermediate computations to at least three decimal places. Round your answers to one decimal place. (If necessary, consult a list of formulas.)Lower limit: Upper limit:

A group of statistics students decided to conduct a survey at their university to find the average (mean) amount of time students spent studying per week. Assuming a population standard deviation of twenty three hours, what is the required sample size if the error should be less than three hours with a 95% level of confidence?

A motel proprietor asks new guests who arrive by car where they started their journey from that day. After three months, he has collected data on 50 carloads of guests. He goes through his records and calculates the distance (in km) travelled by carload of guests. The mean is 195km with a standard deviation of 42.3km.A 95% confidence interval for the average distance travelled is closest to