Question

In a July 2001 research note, the U.S. Department of Transportation reported the results of the National Occupant Protection Use Survey. One focus of the survey was to determine the level of cell phone use by drivers while they are driving a motor passenger vehicle. Data collected by observers at randomly selected intersection across the country revealed that in a sample of 1165 drivers, 35 were using their cell phone.

(a) Check and verify the two conditions for a 98% confidence interval.

(b) Compute a 98% confidence interval for the proportion of drivers that are using their cell phones. Show the set-up for the interval.

There are many ways to measure the reading ability of children. Research designed to improve reading performance is dependent on good measures of the outcomes. One frequently-used test is the DRP, or Degree of Reading Power. It is known that the distribution of DRP scores is normally distributed. A researcher suspects that the mean score µ of all third-graders in Henrico County Schools is different from the national mean, which is 32. To test her suspicion, she administers the DRP to a random sample of 22 Henrico County third-grade students. Their scores are recorded in the following table:

40 26 39 17 42 18 24 43 46 27 19

47 19 26 37 34 15 45 41 39 31 46

(a) Find the t critical value for a 90% confidence interval for the true mean, µ, of the population.

(b) State and verify the conditions for the confidence interval.

(c) Compute and interpret the 90% confidence interval for the mean DRP score in Henrico County Schools. (You can find your point estimate and standard error in your calculator using the 1-Var Stats function. Compare your answers with a classmate to make sure you entered things in correctly!)

(d) Use the confidence interval you constructed in Part (c) to comment on whether you agree with the researcher’s suspicion. Explain your reasoning clearly.

Answer #1

There are many ways to measure the reading ability of children.
Research designed to improve reading performance is dependent on
good measures of the outcomes. One frequently-used test is the DRP,
or Degree of Reading Power. It is known that the distribution of
DRP scores is normally distributed. A researcher suspects that the
mean score µ of all third-graders in Henrico County Schools is
different from the national mean, which is 32. To test her
suspicion, she administers the DRP...

1. There are many ways to measure the reading ability of
children. Research designed to improve reading performance is
dependent on good measures of the outcomes. One frequently-used
test is the DRP, or Degree of Reading Power. It is known that the
distribution of DRP scores is normally distributed. A researcher
suspects that the mean score µ of all third-graders in Henrico
County Schools is different from the national mean, which is 32. To
test her suspicion, she administers the...

1. Find the area under the standard normal curve (round to four
decimal places)
a. To the left of z=1.65
b. To the right of z = 0.54
c. Between z = -2.05 and z = 1.05
2. Find the z-score that has an area of 0.23 to its right.
3. The average height of a certain group of children is 49
inches with a standard deviation of 3 inches. If the heights are
normally distributed, find the probability that a...

Delta airlines case study
Global strategy. Describe the current global
strategy and provide evidence about how the firms resources
incompetencies support the given pressures regarding costs and
local responsiveness. Describe entry modes have they usually used,
and whether they are appropriate for the given strategy. Any key
issues in their global strategy?
casestudy:
Atlanta, June 17, 2014. Sea of Delta employees and their
families swarmed between food trucks, amusement park booths, and
entertainment venues that were scattered throughout what would...

ADVERTISEMENT

Get Answers For Free

Most questions answered within 1 hours.

ADVERTISEMENT

asked 32 minutes ago

asked 46 minutes ago

asked 1 hour ago

asked 1 hour ago

asked 1 hour ago

asked 1 hour ago

asked 2 hours ago

asked 2 hours ago

asked 2 hours ago

asked 2 hours ago

asked 2 hours ago

asked 2 hours ago