Exam 5: Approximating With a Distribution

Use the following Robins are common birds in North America. Suppose that the wingspan of robins is approximately normal with mean 14 inches and standard deviation 0.7 inches. -What proportion of robins have wingspans between 12.5 and 13.5 inches? Report your answer with three decimal places.

Use the following A set of hypotheses, some information from one or more samples, and a standard error from a randomization distribution are provided. Find the value of the standardized z-test statistic. -Test H_o: p = 0.75 versus H_a: p > 0.75 when the sample has n = 20, = 0.78, and SE = 0.015.

Use the following Use the provided density function to choose the best estimate for the proportion of the population found in the specified region. -The percent of the population that is more than 100 is closest to

Use the following A student suspects that the length of songs currently on his iPod are approximately normally distributed with a mean of 257 seconds and standard deviation 62 seconds. -What proportion of songs are less than 180 seconds (3 minutes)? Report your answer with three decimal places.

Use the following The gas prices for a random sample of n = 10 gas stations in the state of Illinois on August 8, 2012 have a mean $3.975, with standard deviation $0.2266. -The bootstrap distribution, based on 5,000 samples, is provided. Would it be appropriate to use the normal distribution to construct a confidence interval for the mean gas price in Illinois on August 8, 2012? Explain briefly.

Use the following Robins are common birds in North America. Suppose that the wingspan of robins is approximately normal with mean 14 inches and standard deviation 0.7 inches. -What is the 30th percentile of robin wingspans? Report your answer with two decimal places.

Use the following Use the provided density function to choose the best estimate for the proportion of the population found in the specified region. -The percent of the population that is more than 50 is closest to

Use the following Find the p-value based on a standard normal distribution for the standardized test statistic and provided alternative hypothesis. -z = -1.86 for

Use the following Select the answer closest to the specified areas for a N(0, 1) density. -The area between z = 0.51 and z = 2.79.

Use the following Heights of 10-year-old girls (5th graders) follow an approximately normal distribution with mean = 54.4 inches and standard deviation of = 2.7 inches. -What proportion of 10-year-old girls have heights between 50 and 55 inches? Report your answer with three decimal places.

Use the following Find the z* values based on a standard normal distribution for each of the following. -A 78% confidence interval for a mean.

Use the following Find the endpoint(s) on a N(0, 1) density with the given property. -The area to the left of the endpoint is about 0.2.

Use the following Final grades in Professor Albert's large calculus class are approximately normally distributed with a mean of 76 (%) and standard deviation of 8 (%). -The top 30% of students earned scores above what value? Report your answer with one decimal place.

Use the following Final grades in Professor Albert's large calculus class are approximately normally distributed with a mean of 76 (%) and standard deviation of 8 (%). -What proportion of students earn between an 82% and 88% in this class? Report your answer with three decimal places.

Use the following Find the z* values based on a standard normal distribution for each of the following. -An 86% confidence interval for a proportion

Use the following Heights of 10-year-old girls (5th graders) follow an approximately normal distribution with mean = 54.4 inches and standard deviation of = 2.7 inches. -What proportion of 10-year-old girls are shorter than 48 inches (4 feet)? Report your answer with four decimal places.

Use the following A student suspects that the length of songs currently on his iPod are approximately normally distributed with a mean of 257 seconds and standard deviation 62 seconds. -What proportion of songs are longer than 300 seconds (5 minutes)? Report your answer with three decimal places.

Use the following Select the answer closest to the specified areas for a N(0, 1) density. -The area to the right of z = -0.47

Use the following Select the answer closest to the specified areas for a normal density. -The area between 43 and 100 on a N(75, 15) distribution.

Use the following In the following, convert an area from one normal distribution to an equivalent area for a different normal distribution. Show details of your calculation. Draw sketches of both normal distributions, find and label the endpoints, and shade the regions on both curves. -The middle 90% for a standard normal distribution converted to a N(45, 15) distribution.