A researcher is interested in finding a 95% confidence interval for the mean number of times per day that college students text. The study included 133 students who averaged 30.4 texts per day. The standard deviation was 22.7 texts. Round answers to 3 decimal places where possible. a To compute the confidence interval use a distribution. b. With 95% confidence the population mean number of texts per day is between and texts. c. If many groups of 133 randomly selected members are studied, then a different confidence interval would be produced from each group. About number of texts per day and about day percent of these confidence intervals will contain the true population percent will not contain the true population mean number of texts per

Suppose that the distance of fly balls hit to the outfielder ( in baseball) is normally distributed with a mean of 250 feet and a standard deviation of 50 feet. We randomly sample 49 fly balls.a. In words define the random variable. X________.b. What is the probability that the 49 balls traveled an average at least of 240 feet. Include a complete shaded graph, and write the probability statement. c. Find the 90th percentile of the distribution of the average of 49 fly balls.

A group of five friends are long-distance runners who will be running in an upcoming marathon. To prepare for the marathon, each of the friends recorded the number of miles they ran each week for 12 weeks. The results of the friends' training are shown in the data set provided below. Which of the friends was the most consistent with the number of miles run each week during the training? Hint: You should not need to compute the standard deviation for each friend. Ashton Caleb Jordan Kyle Noah 24 35 22 15 13 34 36 39 26 29 25 34 26 24 18 31 35 41 25 31 19 37 38 27 15 33 35 37 24 19 27 34 40 25 27 29 36 27 26 32 36 35 21 32 15 16 33 42 24 17 18 36 33 21 28 26 35 35 27 21

We would like to create a confidence interval for the mean. Which of the following would produce the smallest margin of error? Select one: a.A 95% confidence level and a sample size of 150 subjects b. A 99% confidence level and a sample size of 600 subjects. c. A 99% confidence level and a sample size of 150 subjects. d.A 95% confidence level and a sample size of 600 subjects.

A successful basketball player has a height of 6 feet 11 ​inches, or 211 cm. Based on statistics from a data​ set, his height converts to the z score of 5.17. How many standard deviations is his height above the​ mean?

Suppose we wish to calculate a 90% confidence interval for the average amount spent on books by freshmen in their first year at a major university. The interval is to have a margin of error of $2. Assume that the amount spent on books by freshmen has a normal distribution with a standard deviation of $30. How many observations are required to achieve this margin of error?

The 95% confidence interval of the variance of a population is computed as (12.367,21.761). Interpret this confidence interval.

Imagine the mean women’s foot size is a 7.5 with standard deviations of 1.5. a. What percentage of women have a foot size larger than 10? b. If you select 30 people at random is it likely that any of them will have a foot size larger than 10? If so, how many?